SWITCHGEAR, UNIT SUBSTATIONS & MEDIUM VOLTAGE BUS

Power-zone Load Center Unit Substations
Power-zone III Series 2 Switchgear
Power-zone 4 Switchgear
Metal-Enclosed Load Interupter Switchgear
27 Kv MASTERCLAD Medium Voltage Switchgear


Power-zone Load Center Unit Substations





Secondary Unit Substation

Primary Unit Substation

The unit substation is a vital piece of equipment to be consid-ered when planning industrial, commercial, and institutional electrical system demands. Square D Company can provide a unit substation to receive up to 34,500 volts, transform this to a lower utilization voltage, and control its distribution to nearby load areas. Square D Company is a single source supplier of both primary and secondary unit substations.

Square D considers the unit substation as a single product that is designed, coordinated, assembled, and tested at different manufacturing locations as multiple self-enclosed pieces of equipment intended for connection at the jobsite. Various com-binations of incoming sections, transformer sections, and dis-tribution sections make possible a variety of designs

Both Square D Company’s primary unit substations and sec-ondary unit substations are designed, manufactured, and tested in accordance with ANSI C37.121-1989 and other applicable ANSI standards, and the applicable standards of NEMA, UL, and IEEE.

When designing a unit substation, refer to the typical arrange-ments shown in Section 10 of ANSI C37.121-1989. It is also important to consider the environmental conditions, system conditions, installation conditions, and load requirements as outlined in ANSI C37.121-1989.

A unit substation offers the following operational and economical advantages:

Savings

Medium voltage power is purchased at a lower rate than low voltage power can be purchased. Transformation to the utiliza-tion voltage at the load center replaces long, high current low voltage feeder circuits with less expensive primary cable in the distribution system.

Better System Performance

Primary voltage distribution systems feeding load center transformers will minimize system voltage drop and improve voltage regulation. Unit substations also divide the electrical system into independent load areas, which isolates each area from the rest of the system.

Safety

Live parts of all electrical devices are completely enclosed in a grounded steel enclosure. For separate accessibility, internal steel barriers isolate the incoming line, transformer, and low voltage distribution sections from each other. All equipment is designed and built in accordance with the latest NEMA and ANSI standards. Some components of the unit substation are UL Listed.

Ease of Installation

The equipment is divided into factory coordinated shipping sections for ease of handling at the jobsite. Hardware is pro-vided for the connections. Incoming and outgoing connections are accessible for ease of installation.

New unit substations are easily added to primary voltage distribution systems with little effect on the existing equipment. Additional incoming line or low voltage distribution sections can be added to an existing unit substation.

Maintenance

The equipment consists of components designed for minimum maintenance. Refer to operation and maintenance manuals for each section.

Seismic Calculations Seismic calculations are available for most Square D substa-tion equipment to show that when anchored as recommended, they will remain anchored during a seismic event. All seismic calculations are made per the Uniform Building Code. For QED Switchboards, seismic calculations are not available, but QED Switchboards have been tested and are seismically qualified up to seismic zone 4 when anchored as recommended

Manufacturer’s Responsibilities Unit substations are engineered and manufactured by Square D Company. A single warranty covers the entire unit substation. Square D Company also has a field services division which is available for start-up service along with other services.

Metal-Enclosed, Type HVL, Medium Voltage
Load Interrupter Switchgear
Fusible Interrupter


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General Description

Metal-Enclosed VISI/VAC ®, Medium Voltage
Circuit Interrupter Switchgear


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General Description

MASTERCLAD™ Metal-Clad Switchgear

Typical NEMA Type 1 Switchgear Assembly
General Description

QED POWER-STYLE ® Switchboards

General Description

QED Secondary Mains
General Description

QED Distribution Section
General Description

I-LINE Distribution Section

QMB/QMJ Distribution Section

QED-3 Distribution Sections

General Description

QED-4 Distribution Sections

General Description

Dry Type Transformers

General Description

Accessories

Special Applications

Unusual Service Conditions

POWER CAST Transformers – Vacuum Cast

Resin Coils
General Description


Optional Accessories

Special Applications

Unusual Service Conditions

UNI-CAST™ Transformers – Primary Coil –

Vacuum Cast Resin; Secondary Coil – VPI
General Description


Optional Accessories

Special Applications

Liquid-filled Transformers

General Description

Standard Features

Optional Accessories

Special Applications

Model 5/6 Motor Control Centers

Model 5 Standard Features

Busway Systems

I-LINE/I-LINE II Busway

100 A Plug-In Busway

POWER-ZONE ® Metal-Enclosed Busway

Type 36 Compact Sectional Unit Substation

General Description

Compact sectional load center unit substations permit easy handling through existing doors and hallways. They can be installed in locations where physical space limitations will not permit the installation of a conventional load center unit sub-station.

Besides having less depth, the compact design requires front access only. The transformer’s rectangular barrel wound core and coil and enclosure design requires no ventila-tion from the rear (ventilated rear panels are provided).

Incoming Primary Load Interrupter Switchgear - HVL

Secondary Main and Distribution Sections - QED-2
POWER-STYLE Switchboard
Main Section

Distribution Section

VPI Power-Dry Transformer Ratings



Power-zone III Series 2 Switchgear





General

POWER-ZONE ® III Series 2, low voltage metal-enclosed drawout switchgear is premium distribution equipment designed to offer the user many operational security features: minimum down-time, system selectivity, ease of maintenance, and large functional capacity. The Types DSII (not fusible) and DSLII (fused) low voltage power circuit breakers are the primary components of POWER-ZONE III switchgear. These circuit breakers employ a solid state tripping device offering the latest in circuit protection.

Functional and operational advantages are:

Operational Security Features – Compartmentalized and barriered construction per ANSI C37.20.1. Dual steel-front barriers: one as the full cell door covering the circuit breaker manual operation controls and one as the front of the circuit breaker element covering the circuit breaker mechanism.

Minimum Down-Time – Drawout construction allows quick and simple replacement of breaker elements. If an emergency occurs, breakers may be removed from low-priority circuits and re-installed to serve high-priority circuits.

Ease of Maintenance – Circuit breakers are simple to inspect, adjust, and replace. They can be withdrawn from their compartments for convenient maintenance or inspection.

Functional Capacity – Large frame sizes and high withstand rating make the DSII and DSLII low voltage circuit breakers ideal for application on today’s high capacity distribution systems.

System Selectivity – The solid state trip devices provided on each DSII and DSLII low voltage power breaker are field adjustable, enabling the user to attain optimum selectivity and coordination.

UL ® Listing – POWER-ZONE III Series 2 switchgear can be designed and engineered to comply with UL requirements. As an option, DSII and DSLII power circuit breakers are available with a UL listing. Where UL coverage exists for all component material, parts and devices in a switchgear section, a UL label can be affixed.

For Additional Information – POWER-ZONE III Series 2 switchgear is described in general but brief terms here. More detailed and comprehensive data is also available from your local Square D sales office.

Ratings:

Main Bus – 5000 A maximum
120/208 to 600 Vac, 1Æ3W, or 3Æ4W.

Available Breakers:

DSII, DSLII-308, DSII-508, DSII-608 800 A Frame
DSII, DSLII-516, DSII-616 1600 A Frame
DSII-620 2000 A Frame
DSII, DSLII-632 3200 A Frame
DSII, DSLII-840 4000 A Frame
DSII-850 (Forced air cooled) 5000 A Frame

Features:

Indoor Enclosures
Compartmentalized construction:

POWER-ZONE III Series 2 low voltage drawout switchgear offers high reliability through compartmentalized construction.

The three compartments are:

Isolation between the bus and cable compartments and/or between adjacent bays is available through optional vertical barriers.

Outdoor Enclosures

POWER-ZONE III switchgear is available in a walk-in POWER ZONE ® center enclosure for outdoor installation. A non-walk-in enclosure is also available. Both enclosures are NEMA Type 3R as standard.

Non-walk-in enclosures are equipped with:

POWER ZONE™ Center – Walk-In Enclosure

The POWER ZONE center–walk-in enclosure is equipped with the following standard features:

POWER-ZONE III Series 2 switchgear uses the Type DSII low-voltage power circuit breaker. This circuit breaker is available in six basic frame sizes that are tabulated along with their respective interrupting capacities. The breaker overcurrent protection consists of a solid-state, microprocessor based trip device that requires no external power source. The complete tripping system has three basic components: the molded sensors, the trip device (with rating plug), and the trip actuator. The microprocessor-based trip unit uses RMS current level sensing.

Each pole of the circuit breaker is equipped with a molded sensor located on the bottom rear main disconnect contacts. These sensors produce an output proportional to the load current. The output is fed into the trip device, which has the intelligence and energy to operate the trip actuator when required. The trip actuator receives the tripping pulse (from the microprocessor-based trip unit) and mechanically trips the circuit breaker.

Type DSII circuit breakers are equipped with the controls (see Figure 4 on page 6). All circuit breakers are fully stored energy devices with a two-step operating mechanism. A spring charging handle charges the mechanism and the circuit breaker contacts are closed by pushing the “Push To Close” button, which is located on the face of the circuit breaker. Electrically operated circuit breakers have a motor to charge the stored energy mechanism, electric close feature, and electric open feature.

POWER-ZONE III Series 2 LV Drawout Switchgear with POWERLOGIC Circuit Monitors

POWER-ZONE III Series 2 low voltage drawout switchgear is available with the Square D POWERLOGIC circuit monitoring metering, data acquisition, and control system.

Basic circuit information, such as amperes and energy consumption, as well as circuit breaker remote operation, can be accomplished using the POWERLOGIC DIGITRIP 810D trip unit. For more sophisticated metering, power quality monitoring, data acquisition, and control, POWERLOGIC circuit monitors should also be considered.

POWERLOGIC circuit monitors replace a variety of discrete meters, transducers, and other components. POWERLOGIC circuit monitors perform these functions:

Industry standard RS-485 data communications allow the POWERLOGIC system to replace multiple transducers, analog wires, and analog-to-digital conversion equipment. Extensive information can be transmitted over a single communications cable to a POWERLOGIC system display, a personal computer, programmable logic controller, or other host system.

In addition to its metering capabilities, the POWERLOGIC system is available with optional status inputs and relay outputs for monitoring discrete contacts and remote control of devices via the data communications channel. A POWERLOGIC circuit monitor, equipped with a “waveform capture” function, offers a highly accurate class of circuit information, not presently available on the built in trip unit devices. Comprehensive profiles of current and voltage waveforms, suitable for harmonics studies and other power quality analyses, are reported on user-command.

The main disconnecting contacts on the rear of the circuit breaker are spring loaded and self-aligning to ensure positive electrical contact when the circuit breaker is in the connected position. These contacts are designed so the pressure at the point of contact on the stationary stud becomes greater under short circuit conditions.

The secondary disconnecting contacts are also located on the rear of the circuit breaker element and are used for connecting the accessories to the control power source or other control circuits. These contacts are in the “make” position when the element is in the “Connected” and “Test” positions.

POWER-ZONE III Switchgear is also available with fused power circuit breakers. Fused circuit breakers have a short circuit interrupting fusing of 200,000 A symmetrical. The circuit breaker element, including the microprocessor-based tripping system, is identical to that of a non-fusible circuit breaker except for the addition of the fuses and other circuitry necessary for the proper functioning of the fuse protection system.

Current limiting fuses are available on the 800 A, 1600 A, 3200 A, and 4000 A frame power circuit breakers. The current limiting fuses are mounted integrally on the rear of the circuit breaker element for the 800 A and 1600 A frame sizes and are mounted on a separate drawout truck for the 3200 A and 4000 A frame sizes. When fuses are mounted on a separate fuse truck, the drawout mechanisms are mechanically key interlocked with the circuit breaker element. The Square D 3200 A and 4000 A fused circuit breaker design permits mounting both the fuse drawout truck and circuit breaker element in the same vertical section

All versions of the fused circuit breaker are equipped with blown fuse indication and anti-single phasing as standard.

Fused circuit breakers of like frame sizes are interchangeable as standard.

Test and Maintenance Option

All Type DSII and DSLII power circuit breakers equipped with microprocessor-based trip devices have a built-in test feature, as well as plug-in type test facilities that enable the user to test all tripping functions.

The DSII circuit breaker test cart provides mobility for moving circuit breakers to the test area, a convenient height for visual inspection of circuit breakers, contacts for testing all secondary control functions, means for verification of mechanical operation, and a test equipment shelf for mounting the test kit.

Miscellaneous Circuit Breaker Options and Accessories

A rail-mounted traveling type circuit breaker lifting device is optionally available with indoor type switchgear. It is supplied as standard with outdoor walk-in enclosures.

Interrupting Ratings of Type DSII Circuit Breaker (RMS Symmetrical Amperes)

Available Sensors

Available Rating Plugs





Power-zone 4 Switchgear





PRODUCT DESCRIPTION

Introduction

POWER-ZONE ® 4 low voltage metal-enclosed drawout switchgear is designed to provide superior electrical distribution, protection, and power quality management for the entire facility. The prime component of the switchgear is the MASTERPACT ® NW ANSI rated circuit breaker. POWER-ZONE 4 switchgear is designed to maximize the functionality of the MASTERPACT NW circuit breaker, which, in turn, delivers maximum uptime, system selectivity, ease of maintenance and circuit protection. All of this in the smallest footprint available for low voltage drawout switchgear.

Features and Benefits

Compartmentalization

Structures are compartmentalized and are built with barriers as required by ANSI C37.20.1. The structure has large conduit space within the main and feeder sections.

UL Listing

POWER-ZONE 4 switchgear is designed and engineered to comply with UL1558 requirements. MASTERPACT NW circuit breakers are UL1066 listed. A UL label can be affixed where UL coverage exists for all component material, parts, and devices in a switchgear section.

Functional Capacity

High current carrying capacity frame sizes and high withstand rating make the MASTERPACT NW circuit breaker ideal for application on today’s high capacity distribution systems.

Maximum Uptime

Drawout construction allows quick and simple replacement of circuit breaker elements. If an emergency occurs, circuit breakers may be removed from low-priority circuits and re-installed to serve high-priority circuits.

Ease of Maintenance

MASTERPACT NW circuit breakers provide disconnecting and overload protection for the circuit it controls. Each is contained in an individual compartment and can be easily isolated from the energized circuit and withdrawn from the compartment for quick inspection, maintenance, or replacement. The entire switchgear or any other feeder circuits need not be shut down during this operation, thus minimizing production downtime.

Auxiliary Instrument Compartments

Optional control power transformers, meters, and other control devices can be mounted in the auxiliary instrument compartments. These compartments are furnished with hinged doors for easy access. Secondary Horizontal and Vertical Wireways

The secondary wiring design allows for front access to circuit breaker control and communications wiring without removing the circuit breaker from its compartment. The vertical wireway is located on the right side of the circuit breaker for easy access and wiring installation. The horizontal wireway is located directly above the circuit breaker, providing direct access to control and communication terminations.

ANSI Interrupting and Short-Time (Withstand)

POWER-ZONE 4 switchgear with MASTERPACT NW circuit breakers has the highest interrupting and short-time (withstand) ratings for low voltage switchgear in the smallest physical size. The elimination of limiter fuses for high interrupting circuit breakers reduces space and cost. The ANSI rated circuit breaker’s improved coordination with downstream devices increase system uptime.

Through-the-Door Construction

MASTERPACT NW circuit breakers provide clear access to all circuit breaker controls, indicators, and trip unit functionality without opening the compartment door. Circuit breaker racking is also achieved with the compartment door closed.

Disconnecting Contacts

The main disconnecting contacts (power plug-on fingers) on the rear of the circuit breaker are spring loaded and self-aligning to ensure positive electrical contact when the circuit breaker is in the connected position. The secondary disconnecting contacts are located on the top front of the circuit breaker element and are used for connecting the accessories to the control power source, other control circuits, or communication circuits.

MICROLOGIC Enhanced Functionality

A new family of MICROLOGIC electronic and programmable trip units provide you with a choice of expanded information, power quality readings, and communication capabilities. MICROLOGIC trip units can be integrated into the optional POWERLOGIC system.

POWERLOGIC Monitoring System

POWER-ZONE 4 switchgear is available with the POWERLOGIC metering, data acquisition, and control system. The optional POWERLOGIC system is used in addition to, or in lieu of, the Type A, Type P, and Type H MICROLOGIC trip units for the MASTERPACT NW circuit breaker. POWERLOGIC functions are included in MICROLOGIC high-end trip units. Several highly accurate circuit monitors are available to work in conjunction with the POWERLOGIC System Manager Software to manage and control your electrical distribution system.

Equipment Standards

All POWER-ZONE 4 switchgear is 100% rated; assembled and tested in an ISO 9001 facility to applicable standards including:

All MASTERPACT NW circuit breakers are 100% rated; assembled and tested in an ISO 9001 facility to applicable standards including:



GENERAL AND APPLICATION INFORMATION

POWER-ZONE 4 switchgear with MASTERPACT NW circuit breakers provide the necessary switchgear solutions in an industrial environment. The switchgear is designed for ease of use, system selectivity, system uptime, and low maintenance. The switchgear is easy to operate and maintain because of the technological advances in communications, power quality monitoring, and measuring capabilities.

The switchgear with drawout MASTERPACT NW circuit breakers provide overload, short-circuit, and ground fault protection for circuits up to 600 volts. All trip unit and circuit breaker functions are operational from the front without opening the circuit breaker compartment door. MASTERPACT NW circuit breakers carry the highest interruption ratings without fuses and require minimal space.

All MASTERPACT NW circuit breakers can be equipped with MICROLOGIC electronic and programmable trip units to provide you with a choice of expanded information, power quality measurement, protection, and communication capabilities. Additionally, the optional high-end MICROLOGIC trip units are compatible with the optional POWERLOGIC system.

The optional POWERLOGIC data communications system can be used in lieu of or in addition to MICROLOGIC trip units. The POWERLOGIC system uses highly accurate circuit monitors that work in conjunction with its System Manager Software to manage and control your electrical distribution system. POWER-ZONE 4 switchgear is commonly found as the electrical service in the following applications:

Structure

The switchgear assembly is composed of vertical sections arranged according to customer requirements. Each section is divided into a maximum of four compartments. One or more of these compartments can be used as an auxiliary instrument compartment containing potential transformers, meters, relays, and control devices.

A horizontal secondary wireway, containing the accessory terminal blocks is directly above each circuit breaker. A spacious vertical wireway is on the right side of each circuit breaker compartment that allows wire routing through the switchgear.

POWER-ZONE 4 switchgear offers

compartmentalized construction. Each vertical section consists of three compartments: a front compartment (including secondary wireway), a bus compartment, and a rear cable compartment. The front compartment is divided into a maximum of four compartments that can contain MASTERPACT NW circuit breakers or auxiliary equipment. If desired, all compartments may be used for auxiliary equipment, circuit breakers, or a combination. The circuit breaker is positioned to allow ample room for control and communications wiring. Hinged doors on the auxiliary instrument compartment are available for mounting meters, relays, or other control equipment when it does not contain a circuit breaker. A circuit monitor display may be mounted on the hinged door of a compartment containing a main circuit breaker.

Enclosures
NEMA Type 1 Indoor Enclosures

The standard POWER-ZONE 4 switchgear enclosure is NEMA Type 1, general purpose. NEMA Type 1 enclosures are dead front, metal-enclosed structures. All sheet steel parts of the enclosure, inside and out, are painted using an electro-deposition process. Standard Features:

Available Options:

NEMA Type 3R Non-Walk-In Enclosures
Standard Features:

Available Options:

NEMA Type 3R Walk-In Enclosures
Available Options:

Standard Features:

Control and Communications Wiring
Top Control Conduit Entrance

Control and communication wiring is installed and connected from the front of the switchgear. The secondary wiring design allows for circuit breaker compartment wiring without removing the circuit breaker from its compartment.

Control Conduit Entrances

The control wiring conduit entrance is in both the top and bottom of each section for maximum flexibility.

A removable top plate (4-inch by 5-inch) can be punched easily; up to four individual 3/4-inch control conduits per section.

Two bottom conduit entrances in each circuit breaker compartment permit cables to exit through the bottom of the compartment.

Horizontal Wireway

The secondary horizontal wireway is directly above each circuit breaker compartment, allowing easy access to finger-safe secondary terminals. Each secondary terminal is dedicated to a specific function, allowing standardized wiring.

The secondary disconnecting contacts are on the top front of the circuit breaker element and connect the accessories to the control power source or other control circuits. These contacts are in the connected position when the circuit breaker is in the connect and test positions.

Vertical Wireway

The vertical wireway is on the right side of the circuit breaker for quick and easy wiring installation. Control and Communications Terminals

All accessory terminals are on a connecting block on the top front of the circuit breaker cradle and are accessible from the front, even with the circuit breaker in the test or disconnect position. This is particularly useful for field inspection and modification. The field-installable electrical accessories are UL Listed.

Rear Cable Compartment

The rear cable compartment is behind the bus compartment. It provides room for rear access cable installation. Silver plated copper load bars extend from the load side of the circuit breaker stationary connecting contacts into the cable compartment. Cable terminations on the load bars permit cables to exit through either the top or bottom of the vertical sections.

Bus Compartment

The bus compartment contains the horizontal and vertical bus, and is between the circuit breaker compartment and the cable compartment. The bus compartment is separated from the circuit breaker compartment with grounded steel barriers. The optional side and rear barriers isolate the bus compartment from the rear cable compartment. In addition, service entrance barriers provide isolation around the incoming lines to meet UL and NEC requirements. Optional insulated bus aids in protecting the bus in harsh environments.

On four-wire systems, a neutral bus extends the length of the line-up and includes taps for the neutral cables in each vertical section. Feeder circuit breaker neutral sensors (current transformers) are provided on these taps when ground fault protection is supplied. A removable link to the ground bus is furnished, but not connected in the main vertical section for grounded, four-wire systems. The ground bus is a plated copper bus bar and is bolted to the rear bottom of the cable compartment and extends the entire length of the switchgear.

All bus joints use a minimum of two grade-5 bolts and are secured with conical-type spring washers for maximum joint integrity. Bus sizing is based on ANSI/IEEE C37.20.1 continuous current test criteria. Standard bus is plated copper and is fully rated. All vertical and cross bus ratings in POWER-ZONE 4 switchgear are based on a standard temperature rise of 149 °F (65 °C) above a maximum ambient air temperature of 104 °F (40 °C).

Auxiliary Instrument Compartments

Auxiliary instrument compartments are the same size as circuit breaker compartments. Typical auxiliary instrument compartments contain control power transformers, control components, meters, relays, and other optional devices. Circuit monitor displays and other metering devices can be mounted on the door.

Auxiliary Sections

Optional, full-height, auxiliary sections with hinged front doors are available that can be bolted to feeder and main switchgear sections. In addition, auxiliary sections can be provided with through bus as needed.

Key Locks and Padlocks

Optional key locks and padlocks can be provided for the door latches on circuit breaker compartments, auxiliary instrument compartments, auxiliary sections, and the rear doors on switchgear sections. Moving and Handling Options

POWER-ZONE 4 switchgear enclosures are designed to withstand the rigors of lifting, handling, shipping, and setting into place; either as a single unit or as multiple units assembled together within a shipping group. Maximum sizes are determined by shipping dimensions required for transportation on common carrier trucks and movement through standard equipment location openings (door and portals).

Moving and Handling Options

The circuit breaker lifter bar is used with both 3-pole and 6-pole MASTERPACT NW circuit breakers. The size of the circuit breaker determines whether the inside or outside notches on the lifter bar will be used.

Traveling Lifter Assembly

A rail-mounted traveling type circuit breaker lifting device is optionally available with indoor type switchgear. The lifting device is available on enclosures with drip hoods and is capable of lifting MASTERPACT NW circuit breakers into and out of any compartment. The circuit breaker is raised or lowered by manually cranking the hoisting mechanism. The traveling lifter assembly is supplied with outdoor walk-in enclosures.

Floor Crane

In addition, a floor crane can be used with the lifter bar to move a MASTERPACT NW circuit breaker into a dedicated work area.

MASTERPACT NW Circuit Breakers

The primary component of the POWER-ZONE 4 switchgear is the MASTERPACT NW circuit breaker. The drawout circuit breaker design allows easy access to circuit breaker controls, indicators, and the trip unit without opening the circuit breaker compartment door.

MASTERPACT NW circuit breaker features and benefits:

Interrupting Ratings of MASTERPACT NW Circuit Breaker (RMS Symmetrical Amperes)

Available Sensor Ratings

MASTERPACT NW Approximate Operating Time Ratings

MASTERPACT NW Control Power Requirement Ratings

MASTERPACT NW Circuit Breaker Switch Ampere Ratings

Through-the-Door Construction

The closing and opening push buttons, the racking handle, and racking mechanism are accessible through the front door cutout, allowing circuit breaker operation and disconnection without opening the door. Optional shutters can be provided, covering live parts when the circuit breaker is removed.

MASTERPACT NW circuit breakers meet ANSI interlock requirements, including closing spring interlocking. Circuit Breaker Compartment

The circuit breaker compartment consists of the circuit breaker cradle, a horizontal secondary terminal block on top of the cradle, and a vertical wireway on the right side of the compartment allowing for top and bottom customer wiring. The cradle structure is a bolted-in assembly that supports the circuit breaker. Integrated into the cradle are the circuit breaker interference interlocks or cell keys.

Cell keys are steel pins on the left side of the cradle. As the circuit breaker is pushed into the compartment, the bracket on the circuit breaker moves past a corresponding bracket on the cradle. If the circuit breaker is not matched correctly for the compartment, the brackets will interfere and the circuit breaker will not go into the compartment.

Cell keying is a standard POWER-ZONE 4 switchgear feature. The racking crank storage hole, racking crank hole, and “Push Stop Release” button are on the bottom of the cradle. Circuit breaker racking is achieved with the circuit breaker compartment door closed. When required for metering, optional current transformers are positioned around the stationary main contacts.

Interruption and Short-Time (Withstand) Ratings

POWER-ZONE 4 switchgear with MASTERPACT NW circuit breakers have the highest interrupting (200,000 A at 480 V without using fuses) and short-time (withstand) ratings for low voltage switchgear in the smallest physical size. The small switchgear footprint and the elimination of limiters reduces cost. The MASTERPACT NW circuit breaker’s wide range of coordination with downstream devices increases system uptime.

MASTERPACT NW circuit breakers are available in various levels of interrupting ratings (AIR), see “Interrupting Ratings of MASTERPACT NW Circuit Breaker (RMS Symmetrical Amperes)” on page 36. Circuit breakers of like frame sizes and interrupting ratings are interchangeable.

Circuit Breaker Types

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Two-Step Stored Energy Mechanism

MASTERPACT NW circuit breakers are stored energy devices with a two-step operating mechanism. Electrically operated circuit breakers have a motor to charge the stored energy mechanism, electric close feature, and electric open feature. On manually operated circuit breakers, the closing springs are charged by hand. For electrically operated circuit breakers, the springs are charged by an internal electric motor, but can also be manually charged if no control power is available. Status indicators on the front of the circuit breaker indicate when the closing springs are charged or discharged. Circuit Breaker Inspection

When the MASTERPACT NW circuit breaker is withdrawn on its rails, the circuit breaker is accessible for visual inspection. It is easy to remove the arc chutes and visually inspect the contacts and wear indicator. The operations counter can also indicate when inspections and possible maintenance should be done.

Circuit Breaker and Equipment Accessories

A number of MASTERPACT NW circuit breaker accessories are available with POWER-ZONE 4 switchgear. A few of the most common accessories are listed below.

Shutters:

Optional shutters in the cradle automatically block access to the main disconnects when the circuit breaker is in the disconnect, test, or remove position. An optional padlock attachment to lock shutters closed is also available.

Key Interlocks, Key Locks, and Padlocks:

Optional key interlocking can be provided with MASTERPACT NW circuit breakers. Key interlocking capability is available for circuit breaker operation and the cradle.

Key interlock operation is outlined in the POWER-ZONE 4 switchgear order assembly drawings. To facilitate installation procedures, a key is supplied with each lock. After installation, only the necessary keys called out on the key interlock diagrams should be present on the switchgear.

Cell Keying:

Cell keying, a standard feature on POWER-ZONE 4 switchgear, is provided to avoid insertion of circuit breakers with similar dimensions but insufficient interrupting ratings, or incorrect frame sizes into an inappropriate circuit breaker compartment.

Auxiliary Switches:
A family of auxiliary switches that include:

A family of field-installable coils, buttons, motors, connectors, and trip units that include, but are not limited to:

MICROLOGIC Trip Units

A new family of field-installable trip units is available with MASTERPACT NW circuit breakers. The circuit breaker overcurrent protection consists of a solid-state, microprocessor-based tripping device that requires no external power source. The complete tripping system has three main components: the molded sensors, the trip device (with rating plug), and the trip actuator. The microprocessor-based trip unit uses true RMS current level sensing.

When the MASTERPACT NW circuit breaker is closed, no external power is required for the protection system. The trip unit is powered by current signal levels and current sensors integrally mounted in the MASTERPACT NW circuit breaker. All trip units are UL Listed for use in MASTERPACT NW circuit breakers.

Basic Trip Unit

Standard Trip Features:

Available Options:

Type A (Ammeter) Trip Unit

Standard Trip Features:

Available Options:

Available POWERLOGIC

Features:

Type P (Power Metering) Trip Unit

Available Options:

Available POWERLOGIC

Features:

Standard Trip Features:

Type H (Harmonics) Trip Unit

Standard Trip Features:

Available Options:

Available POWERLOGIC

Features:

MICROLOGIC Adjustable Trip Setting Ratings

Functionality

The table below lists the standard and optional trip unit features for MICROLOGIC Type A (Ammeter), Type P (Power Metering), and Type H (Harmonics) trip units for use in POWER-ZONE 4 switchgear.

MICROLOGIC Trip Unit Functionality

POWERLOGIC System

POWER-ZONE 4 switchgear is available with POWERLOGIC metering, data acquisition, and control system features. The POWERLOGIC system is used in conjunction with MICROLOGIC Type A, Type P, and Type H trip units for the MASTERPACT NW circuit breaker. The complete system is comprised of several devices including, circuit monitors, power meters, trip units, programmable logic controllers, digital relays, transformer temperature controllers, I/O, lighting control, and more. System Manager Software is available to work in conjunction with these devices to manage and control your electrical distribution system.

MODBUS industry standard data communications allow the POWERLOGIC system to replace discrete meters, multiple transducers, analog wires, and analog-to-digital conversion equipment. Extensive information can be transmitted over a single communications cable to a POWERLOGIC system display, a personal computer, programmable logic controller, or other host system.

The following MICROLOGIC trip units are POWERLOGIC compatible:

Basic circuit information, such as amperes, can be monitored using MICROLOGIC Type A trip unit. Circuit breaker remote operation is available using the MICROLOGIC Type P, and Type H trip units with POWERLOGIC functionality. For additional information, see the trip unit functionality matrix on page 39. For more sophisticated metering, power quality monitoring, data acquisition and control, POWERLOGIC circuit monitors may also be used.

MICROLOGIC Trip Unit System Summary

In addition to its metering capabilities, the MICROLOGIC trip unit system is available with optional status inputs and relay outputs for monitoring discrete contacts and remote control of devices by way of the data communications channel.

MICROLOGIC trip unit relaying functions include:

MASTERPACT NW circuit breaker maintenance information:

System Components

POWERLOGIC system components and additional features are listed below. Available POWERLOGIC Features:

POWERLOGIC System Components:

Circuit Monitors

POWERLOGIC circuit monitors provide highly accurate meter readings along with disturbance monitoring, analog and digital I/O, onboard logging, and more. Circuit monitors can be mounted on POWER-ZONE 4 switchgear, auxiliary instrument compartments, and auxiliary sections.

Distribution Systems

Wye Solidly Grounded Systems

A Wye system is the most common type of three-phase distribution system for low voltage switchgear. Wye systems are either three- or four-wire distribution systems that are normally grounded, either in the equipment, or at the transformer source

Three-Wire Wye Distribution-Solidly Grounded System

When the system is grounded in the equipment and the neutral phase is carried through the equipment, the system is described as a four-wire solidly grounded system with neutral connections available to supply single phase-to-neutral loads, such as lighting loads.

When the system is grounded at the transformer source and no neutral phase is carried through the equipment, the system is described as a three-wire solidly grounded system. No neutral connections are available; all loads must be three-phase (or single “phase-to-phase”) loads. In some cases, the neutral is delivered to the service entrance where it is bonded to ground similar to the four-wire solidly grounded system.

Delta Grounded and Ungrounded Systems

Formerly common, Delta three-wire systems are rarely used in low voltage distribution systems. Delta three-wire distribution systems can be grounded or ungrounded services. Generally, Delta systems are ungrounded. In some cases, they are grounded on the “corner” of the delta or some other point. Ungrounded Delta systems do not have a reference point or ground. Corner or Grounded B Phase Delta distribution systems do provide a reference point but require one phase to be connected to the ground. Low voltage drawout switchgear with MASTERPACT NW circuit breakers are designed and built to ANSI C37.20.1 and is tested for single phase-to-phase faults. They can be applied on “corner” grounded Delta distribution systems. POWER-ZONE 4 switchgear with MASTERPACT NW circuit breakers are suited for corner grounded or ungrounded systems.

Three-Wire Delta Distribution-Ungrounded

Although ungrounded systems have been used for many years, they are not recommended in newly designed low voltage distribution systems. Ungrounded power systems may be unstable. High resistance grounded systems as shown on pages 56 and 57 are recommended for use in newly designed low voltage distribution systems.

Ground Fault Protection for Wye Systems

The need for ground fault protection in three-phase solidly grounded Wye systems is due to the possibility of low magnitude ground fault currents. Phase-to-phase faults are of such a large magnitude that overcurrent protection devices (trip units) can operate rapidly and positively to signal the circuit breaker to open. Ground faults can be of a much lower magnitude and require specialized elements in the trip unit for detection.

POWER-ZONE 4 switchgear with MASTERPACT NW circuit breakers equipped with MICROLOGIC trip units have the capability of providing ground fault sensing (alarm with no tripping) and ground fault protection (tripping) on three-phase, three-wire and three-phase, four-wire solidly-grounded systems. MASTERPACT NW circuit breakers can be used for overcurrent protection on ungrounded or resistance grounded systems, but are not suitable for ground fault protection on these systems.

Ground faults are an inadvertent flow of current between the normal current-carrying conductors and ground. These ground faults usually start at a low level and, if left undetected, escalate causing significant heat and mechanical damage to the electrical system. Ground faults can escalate to a phase-to-phase fault causing major system damage. The ground fault system in the MASTERPACT NW circuit breaker monitors the flow of current in the system and detects ground fault currents. The circuit breaker will trip to protect the circuit, or send an alarm through the appropriate interface equipment, depending on the option installed.

Ground Fault Protection with Tripping

Ground fault protection is available as an option on MASTERPACT NW circuit breakers with MICROLOGIC 6.0A and higher trip units. MASTERPACT NW circuit breakers offer three different ground fault sensing options: residual, ground-source return and modified differential. The sensing options make it possible to match the number and location of current sensors to the application. The pickup and delay settings for ground fault are adjustable locally with the dial settings or through the key pad. The pickup and delay settings for ground fault are also adjustable remotely over a computer network on MICROLOGIC 6.0 and higher trip units. A neutral current sensor (NCT) must be installed in the neutral if ground fault alarm is used on a three-phase, four-wire system.

Ground Fault Protection without Tripping

All MASTERPACT NW circuit breakers with MICROLOGIC 5.0P and higher trip units come standard with the ability to sense and report a ground fault alarm through the optional programmable contact module or communication network. A neutral current sensor (NCT) must be installed in the neutral if ground fault alarm is used on a three-phase, four-wire system.

The pickup and delay settings for the ground fault alarm are adjustable locally through the key pad on the trip unit or remotely over a computer network.

Residual Ground Fault Sensing

Residual ground fault sensing systems use one current sensor for each current-carrying conductor. The trip unit vectorially sums the secondary outputs from each sensor to determine if there is a ground fault and the magnitude of the ground fault. The following diagram shows the current sensors for a three-phase, four-wire system. There is a current sensor on each phase and the neutral.

Typical Residual Ground Fault Sensing System with Phase Conductors

The sensors for the phase conductors A, B and C are inside the circuit breaker. The neutral current transformer is installed in the neutral circuit. If the circuit breaker were used on a three-phase, three-wire system, the neutral current transformer would not be necessary.

Ground Source Return

Ground source return ground fault sensing systems use one current sensor on the ground conductor. The current sensor measures the ground current flow. The following diagram shows the current sensor for a three-phase, four-wire system. Ground source return can also be used on three-phase, three-wire systems.

Typical Ground Source Return Sensing System with Ground Fault Interface Module and Current Sensor Ground-source return sensing systems require the use of the optional ground fault interface module and a sensor installed in the ground circuit.

The current sensor and ground fault interface module must be wired per the installation and wiring instructions included with the ground fault interface module.

Modified Differential Ground Fault System

A modified differential ground fault system (MDGF) is used for multiple sourced systems. Normal residual and ground-source return systems will not correctly sum all of the circulating currents caused by the multiple neutral paths and multiple grounds. The following diagram shows a typical main-tie-main system. Each source transformer is grounded, and the service entrance neutral is bonded to ground. Multiple neutral paths allow neutral current to circulate and return to the supplying transformer by several different paths. The ground fault system must be capable of correctly summing these circulating currents.

Typical Modified Differential Ground Fault System with Ground Fault Interface Modules

The modified differential ground fault sensing system requires the use of ground fault interface modules and current sensors installed in all normal current-carrying conductors. The current sensors and ground fault interface modules must be wired in parallel and the polarity of the current sensors must be maintained per the installation and wiring instructions included with the ground fault interface module.

High Resistance Grounded Systems

Where continuance of service for your distribution system is a high priority, high-resistance grounding adds the features of a grounded system on an ungrounded system while minimizing the risk of service interruptions resulting from ground faults.

High resistance grounding simultaneously provides a system reference point (or ground) to overcome the negative effects of low level ground faults and limits the magnitude of current that can flow during a ground fault. A resistance value is selected to limit the overvoltage during arcing faults. Industry practice has established that the resistance value should be selected relative to the system capacitive charging current.

An ammeter, in the circuit of a grounding resistor/grounding transformer assembly, reads the total amount of the ground current flowing through the system. When a current-sensing relay is added, any levels in excess of the capacitive charging current can be monitored. Alternatively, a voltmeter-relay (not shown) can be connected across ground resistors to monitor the capacitive charging current in a resistor/grounding transformer assembly. The ground current ammeter provides a linear reading of the existent ac ground current present in the system for both the current and voltage detection methods described above.

Circuit breakers rated to C37.13 are recommended for high resistance grounded systems.

POWER-ZONE 4 switchgear with MASTERPACT NW circuit breakers are rated to C37.13.

Wye Systems Configured

High resistance grounding for Wye-connected systems is established by placing resistors in series with the neutral-to-ground connection of the power source. Grounding resistors are chosen to limit the ground current to a maximum value of five amperes. Line-to-neutral loads cannot be connected to a system where the neutral is resistance-grounded. For additional information, see 1999 NEC 250-36.

Delta Systems Configured

A neutral point must be established in an ungrounded Delta-connected system using three single-phase transformers. Typically, grounding resistors and transformers are chosen to limit the ground current to a maximum value of five amperes. This technique can be applied on Wye-connected sources when the neutral point is not accessible from the service entrance conduit. The neutral point cannot be used to service phase-to-neutral loads.

Automatic Transfer Systems

Automatic transfer systems minimize power interruption by transferring the load from the normal source to an alternate source when the normal source is temporarily unavailable. The system uses multiple connections to power sources, usually utility sources, and a programmable logic controller (PLC) to achieve this transfer. These systems also feature redundant supplies of control power. Examples of automatic transfer systems with main-main circuit breakers and main-tie-main circuit breakers.

Main-Main Circuit Breakers

Each main circuit breaker connects to a utility source. When the normal source becomes unavailable, the system transfers to the alternate. If the system comes equipped with a preferred source selector option, the system reverts to the preferred source automatically once it is available. Without the selector, automatic retransfer does not occur.

Main-Tie-Main Circuit Breakers

Both main circuit breakers, connected to a utility source, are connected together by means of a normally open tie circuit breaker. Each main circuit breaker feeds independent load buses. Various settings of the preferred source selector switch and the retransfer on/off options determine which circuit breakers are closed during various operating conditions.

Special Applications

Seismic Applications

POWER-ZONE 4 switchgear has been tested for applications according to Uniform Building Code (UBC) zone 4 requirements. Equipment must be anchored properly to fully comply with zone 4 installations. Additional information can be found in Bulletin No. 80298-002-01, POWER-ZONE ®4 Low Voltage Metal-Enclosed Drawout Switchgear with MASTERPACT NW Power Circuit Breakers.

High Altitude Applications

When POWER-ZONE 4 switchgear with MASTERPACT NW circuit breakers is installed at a location greater than 6600 feet above sea level, the ratings must be de-rated.



Metal-Enclosed Load Interupter Switchgear





Introduction

The HVL/cc™ Metal-Enclosed Load Interrupter Switchgear from Square D provides switching, metering, and interrupting capabilities for medium-voltage electrical power distribution systems. It is designed to provide better performance and reliability, lower electrical costs, allow ease of system expansion and reduce equipment expense for systems ranging from 2.4 kV to 17.5 kV, 60 kV BIL— 110 kV BIL. This switchgear is noted for its versatility, durability, and convenience. It has proven reliable both as service entrance equipment and in controlling substation transformers and is designed and manufactured in accordance with ANSI/IEEE, NEMA, CAN/CSA, UL and CUL standards C37.20.3, C37.20.4, C37.57, C37.58, CSA 22.2 no. 31, CSA 22.2 no. 193, and NEMA SG5 where applicable.

Made up of modular units, the HVL/cc is easy to expand. Two main bus positions allow future extensions and connections to existing equipment.

HVL/cc switchgear is available in either single or multiple bay units. To simplify handling and installation, each section is assembled before shipping. The design is compact, with front accessibility. The HVL/cc switch can be equipped with either an over-toggle mechanism (OTM), which is standard, or an optional stored energy mechanism (SEM). An option with both mechanisms is the FUSELOGIC™ system. The FUSELOGIC system offers fuse tripping (with SEM) to provide protection against single phasing loads when a fuse has blown. It also has a mechanical interlock to prevent inadvertent switching until fuses have been installed or blown fuses have been replaced. (Additional details on page 5). An optional blown fuse flag is available with either OTM or SEM. The FUSELOGIC system on OTM offers 1 N.O.-1 N.C. auxiliary contact in addition to the blown fuse flag. The mechanical lockout feature is also included on OTM.

Mechanical interlocks are standard. This feature protects the operator by preventing the removal of the load-side panel while the load interrupter switch is closed and/or the optional ground switch is open. HVL/cc switchgear is available for both indoor and outdoor enclosures. Each has features to ensure convenience, reliability, and durability.

Indoor switchgear includes lifting angles at the top corners of each shipping section for ease in handling, provisions for expansion, an 11 gauge steel enclosure, full-length ground bus in multiple bay enclosures, and padlocking for the load-side panel. Optional features include key interlocking and clear windows for inspection of optional load discharge assembly.

The outdoor switchgear is solidly constructed with a rear-sloping roof, a steel welded base and 11 gauge steel enclosure, gasketed front doors and strip heaters in each switch bay. Operating handles are enclosed by outer bulkhead type door.

The HVL/cc enclosure is designed for front access only and with minimum clearance can be positioned against walls, in small rooms or in prefabricated buildings. The small footprint can result in considerable cost savings from the reduction of building or room sizes.

Meter bays are available in both hot and cold sequence designs for Utilities and/or customer requirements (Consult factory for Dimensions and Availability). Special utility metering bays can be provided as with our conventional HVL Metal-Enclosed switchgear.

General

Improved system performance and reliability, lower electrical power cost, easier system expansion, and reduced equipment expense are issues commanding serious attention in 2400 V to 17,500 V electrical power distribution system planning.

Square D Metal-Enclosed Load Interrupter Switchgear functions as a prime component of these systems providing necessary switching and overcurrent protection for the medium-voltage feeders. It is often used in conjunction with Square D unit substations. The switchgear is most frequently applied as service entrance equipment, although it performs equally well in controlling substation transformers and in sectionalizing medium-voltage feeder systems.

Standard Features

The FUSELOGIC ™ System

The new Square D medium voltage current limiting fuse sets the standard for features and protection. The new extended travel blown fuse indicator provides extended travel and increased energy to positively operate this optional feature.

The new FUSELOGIC system also prevents closing the HVL/cc™ switch if a fuse is blown or has not been installed. This reduces the potential of equipment damage due to single phasing because of a blown fuse. The FUSELOGIC system can be used to operate auxiliary contacts for optional local and/ or remote indication or for fuse tripping.

The fuse trip system requires the stored energy mechanism (SEM) with separate close and open springs. The motor operator is optional on both OTM and SEM. For information about the FUSELOGIC system refer to Document number 6040DP9601 the FUSELOGIC system Application Guide or call Square D.

Type of Equipment Available—Indoor and Outdoor Weatherproof

Single Bay Switchgear contains a single fused or unfused switch in a free-standing enclosure. It is ideally suited for locating close to a load to control a single medium-voltage circuit. Special emphasis is placed on conduit area, cable entrance, and terminations. Normally, no main bus is furnished in a single bay. A ground pad bonded to the steel frame is furnished with a cable lug termination. This equipment is designed for front accessibility only and bottom cable entry is preferred.

Multiple Bay Switchgear consists of a lineup of individual feeder switch bays connected to a common main bus. A main switch, fused or not fused, can be included in the lineup with a utility or user metering cubicle, depending upon job requirements. A continuous ground bus is bonded to the frame of each bay for the complete length of the lineup. The end cubicles are furnished with provisions for the addition of future feeder switch bays.

Outdoor Single Switch or Multiple Bay Switchgear

Consists of medium-voltage components in a NEMA Type 3R enclosure. Access is through a gasketed front bulkhead-type door. The enclosure is designed so that the sheared edges of the steel are not exposed. The equipment is furnished with a welded, formed steel channel base and weatherproof paint finish.

HVL/cc™ Load Interrupter Switch Construction

BIL for Available Voltages

4.76 kV, 15 kV, and 17.5 kV

Construction Features of Indoor Equipment

The three tin-plated copper busbars are parallel mounted A, B, C front to rear. 600 and 1200 A main bus is available. Connection is made to the fuses using field shapers.



27 Kv MASTERCLAD Medium Voltage Switchgear





RATINGS

APPLICATIONS AND STANDARDS

MASTERCLAD ® medium voltage metal-clad switchgear is used in a wide variety of switching, control and protective applications including electric utility generation and distribution systems, industrial plants, commercial buildings, hospitals, municipal pumping stations, wastewater treatment plants, transportation systems and pipeline stations.

MASTERCLAD offers a standard two-high breaker arrangement, incorporating a series of basic modular units, control packages and instrumentation that can be assembled in combinations as needed to satisfy user application requirements.

MASTERCLAD switchgear with VR circuit breakers meets or exceeds the design standards of ANSI, IEEE, NEMA and IEC. The switchgear is tested in accordance with both ANSI C37.20.2 and IEC 298. The VR circuit breakers are tested per ANSI C37.09 and IEC 56.

STANDARD FEATURES

Metal-Clad Switchgear as defined by ANSI C37.20.2 includes:

Ratings

VR 27 kV Vacuum Circuit Breakers Rating Table on Symmetrical Current Rating Basis

Weight (Approximate)