5. 5015-21-3104 DMAFB Substation P&C Report - 100%.pdf

SUBSTATION PROTECTION & CONTROLS

REPORT

for

DMAFB Substation Switching and Distribution

FBNV190002

Prepared for:

United States Air Force

Davis-Monthan Air Force Base

Tucson, Arizona

Prepared by:

Infrastructure Engineering Solutions JV

964 5th Ave, Ste 214

San Diego, CA 92101-6102

Project No.: 251230

Issue for Construction

19 January 2024

REV. DATE DESCRIPTION PREPARED VERIFIED APPROVED

0 01/19/2024 100% IFC RASHITH ZORAN GRIFFITH

DMAFB Substation Protection & Controls Report

Design Analysis 19 January 2024

CONTENTS

1. PURPOSE

2. PROJECT DESCRIPTION

3. REFERENCES

4. PROTECTION & CONTROL EQUIPMENT

5. 13.8kV PROTECTION AND CONTROL SYSTEMS

5.1. 13.8kV INCOMINGS FROM PATRIOT SUBSTATION

5.2. 13.8kV OUTGOING FEEDERS TO EXISTING DMAFB SWITCHGEAR

5.3. CAPACITOR BANKS (TWO 6-MVAR UNITS)

5.4. SPARE FEEDER

6. 13.8kV BUSBAR PROTECTION

6.1. 13.8kV BUSBAR 1 PROTECTION

7. GENERAL CRITERIA

7.1. CT CONNECTIONS

7.2. PT CONNECTIONS

7.3. TRIPPING

8. INTERLOCKING

8.1. INTERLOCKING BETWEEN INCOMING FEEDERS

8.2. INTERLOCKING BETWEEN OUTGOING FEEDERS

9. COMMUNICATIONS

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1. PURPOSE

This document will outline the protection and control philosophy that will be implemented in the new 13.8kV E-House Switchgear and existing DMAFB Switchgear. The contractor shall include with their bid an SEL programming package and startup package (for cutover) which shall include all costs to provide a fully functional electrical relay and metering system at DMAFB as described in this document, the Commissioning Plan, Specifications, and construction drawings (electrical, controls, and structural).

The new 13.8kV E-House Switchgear will have a single bus with nine compartments connecting to:

• Two separate incoming feeders from Patriot Substation.

• Two separate 6-MVAR capacitor banks for reactive power compensation.

• Two separate outgoing feeders connecting to the existing DMAFB switchgear.

• One spare feeder breaker for backup and/or future equipment.

• One station service transformer (SST) to feed the new substation E-House.

• One bus potential transformer (PT) for voltage input to meter(s) and protection relays.

The new incoming feeders, outgoing feeders, capacitor banks and spare compartments shall be provided with individual relays for overload, short circuit, and ground fault protection.

The existing DMAFB Switchgear shall be retrofitted with two new incoming vertical sections with MV switches and protective relays connecting to:

• Two separate incoming feeders from Patriot Substation.

2. PROJECT DESCRIPTION

The scope of work is to provide two 13.8 kV primary power distribution circuits to the existing DMAFB substation from the new Patriot Substation owned by Tucson Electric Power (TEP). These new primary feeds will be intercepted, switched, and protected at the new 13.8kV switchgear located in a new substation E-House that feeds the existing DMAFB Switchgear. The new power distribution system is designed such that one 13.8 kV circuit can carry the entire base peak demand load of 24

MVA.

3. REFERENCES

The following references were used for the design of the substation protection and controls system.

Drawing/Document Number Description

E-601 Overall Single-Line Diagram

E-701 Relay One Line Diagram

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4. PROTECTION & CONTROL EQUIPMENT

The new switchgear breaker compartments will contain the protection relays for all the above-mentioned feeders. Relays referenced are manufactured by Schweitzer Engineering Laboratories

(SEL).

1. The following feeder protection relays shall be used for overload, short circuit, and ground fault detection and tripping:

Compartment Number Equipment Relay Model

1 13.8kV Incoming feeder-1 from TEP SEL-751

2 13.8kV Outgoing feeder-1 to existing DMAFB Switchgear

SEL-751

3 6-MVAR Capacitor Bank-1 SEL-751

4 Spare Feeder SEL-751 5 13.8kV-208Y/120V Station Service

Transformer

6 6-MVAR Capacitor Bank-2 SEL-751

7 13.8kV Outgoing feeder-2 to existing DMAFB Switchgear

SEL-751

8 13.8kV Incoming feeder-2 from TEP SEL-751 9 13.8kV-120V Voltage Transformer -

2. The following high-impedance differential relay shall be used for busbar protection:

Compartment Number Equipment Relay Model

9 13.8kV Busbar SEL-587Z

5. 13.8kV PROTECTION AND CONTROL SYSTEMS

5.1. 13.8kV INCOMINGS FROM PATRIOT SUBSTATION

An SEL-751 Feeder Protection Relay (50/51/50G/51G/67/67G/27) with Arc Flash Detection will be installed in each 13.8kV incoming feeder compartment. The relay will receive current input from the current transformer

(CT1) in its compartment, voltage inputs from the 3Ø PTs on the 13.8kV bus and the 1Ø PT on the line. The 1Ø

PT shall be mounted on BØ.

When an arc flash or fault is detected in the either of the incoming feeders, the respective SEL-751 relay will take the following actions:

▪ Energize trip coil 1 (from a dedicated relay output).

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▪ Send an “Inhibit” command to the SEL-751 in the other 13.8kV incoming to prevent it from closing automatically.

▪ Send an “Trip” command to the SEL-751 in the other compartments to prevent reverse feeding the faults.

In case of a relay malfunction by either incoming primary SEL-751s, a “Relay Failure” alarm will be sent to the SEL-751 relay in the other 13.8kV incoming compartment.

Each SEL-751 relay will have one output programmed to close its circuit breaker.

Square D PowerLogic ION-8650 meters will be used in the 13.8kV incoming compartments for power metering of the DMAFB Substation load. The ION meters will receive their current inputs from current transformer (CT2) and its voltage inputs from the 3Ø PTs on the 13.8kV bus. This metering data shall be connected to the existing Controls Building system. The Controls Building is located next to the existing DMAFB Switchgear and contains the substation protection, controls, and metering devices.

5.2. 13.8kV OUTGOING FEEDERS TO EXISTING DMAFB SWITCHGEAR

An SEL-751 Feeder Protection Relay (50/51/50G/51G/67/67G/27) will be installed in each 13.8kV outgoing feeder compartment. The relay will receive current input from the current transformer (CT1) in its compartment and voltage inputs from the 3Ø PTs on the 13.8kV bus.

When any fault is detected in the either of the outgoing feeders, the respective SEL-751 relay will take the following actions:

▪ Energize trip coil 1 (from a dedicated relay output).

In case of a relay malfunction by either outgoing primary SEL-751s, a “Relay Failure” alarm will be sent to the SEL-751 relay in the other 13.8kV outgoing compartment. Each 751 relay will have one output programmed to close its circuit breaker.

The outgoing feeder relays will receive a trip signal from the downstream DAMFB Switchgear relays in the event of a fault or arc flash. The relays will then take the following actions:

▪ Energize trip coil 1 (from a dedicated relay output).

▪ Lockout the other outgoing feeder breaker.

The outgoing feeder breaker will automatically switch to the alternate incoming line if it detects a loss of power on its primary connection.

5.3. CAPACITOR BANKS (TWO 6-MVAR UNITS)

An SEL-751 Feeder Protection Relay (50/51/50G/51G/67/67G,27) will be installed in each 13.8kV capacitor bank feeder compartment. The relay will receive current input from the current transformer (CT1) in its compartment and voltage inputs from the 3Ø PTs on the 13.8kV bus.

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When any fault is detected in either of the outgoing feeders, the associated relay shall energize trip coil 1 using its dedicated trip output.

In case of a relay malfunction by either SEL-751, the associated breaker shall be tripped and a “Relay Failure” alarm will be indicated on the display.

Each SEL-751 relay will have one output programmed to close its circuit breaker.

5.4. SPARE FEEDER

A spare breaker shall be included in the switchgear line-up. This additional breaker shall be used for direct replacement if any of the other breakers need to be maintained or repaired. An SEL-751 Feeder Protection relay (50/51/50G/51G/67/67G/27) will also be included in the spare feeder breaker compartment. This relay can also function as a direct replacement for any of the other relays in the other breaker compartments after reprogramming. Additionally, this spare compartment shall be provided with all the periphery equipment required for DMAFB to add an additional load at a future date.

6. 13.8kV BUSBAR PROTECTION

6.1. 13.8kV BUSBAR 1 PROTECTION

SEL-587Z High Impedance Bus Differential protection relay, 87B1 (87B) will be used for bus protection for

13.8kV Busbar 1. The relay will receive current input from the current transformer (CT3) in all compartments.

For a bus fault, the SEL-587Z relay will energize & operate external lockout relay 86-B1 and the below actions will take place:

• Trips the associated B1-13.8kV breakers: 13.8CB1, 13.8CB2, 13.8CB3, 13.8CB4, 13.8CB5, 13.8CB6

& 13.8CB7.

• Inhibit closing of associated B1-13.8kV breakers: 13.8CB1, 13.8CB2, 13.8CB3, 13.8CB4, 13.8CB5, 13.8CB6 & 13.8CB7.

7. GENERAL CRITERIA

7.1. CT CONNECTIONS

The current transformers (CT) shall be hardwired to each protection relay. Each CT will be configured as a three-phase wye connection. In each compartment, CT1 shall be connected to its respective SEL-751 feeder protection relay. In the 13.8kV incoming feeder compartments, CT2 shall be connected to the ION-8650 meters for usage data. In each compartment, CT3 shall be connected to the SEL-587Z high impedance busbar protection relay.

7.2. PT CONNECTIONS

The potential transformers (PT) shall be hardwired to each protection relay. The single winding from each bus PT shall be connected to the SEL-751 relays in all compartments and shall also be connected to the ION-8650 meters in the 13.8kV incoming feeder compartments.

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7.3. TRIPPING

The SEL-751 relays will energize the trip coil for its respective breaker if a fault is detected.

The SEL-587Z relay will energize the external lockout relay 86-B1 if a bus fault is detected. The 86-B1 relays will energize the trip coils for all breakers.

8. INTERLOCKING

Power transfer between the incoming lines to the new E-House 13.8kv switchgear shall be automatic.

Additionally, power transfer between the outgoing lines to the existing DMAFB switchgear shall also be automatic. The following information details the states and conditions the E-House SEL-751 relays must check prior to initiating a close command to any of its four breakers involved in distributing power to the existing DMAFB switchgear.

8.1. INTERLOCKING BETWEEN INCOMING FEEDERS

Logical interlocks shall be implemented between the incoming SEL-751 relays to prevent both incoming lines from being tied together at the switchgear bus. The following inputs shall be hardwired to maintain this logic.

• Current transformer CT1

• 3 phase potential transformer from bus side

• 1 phase potential transformer from feeder side

• Open Status of Incoming-1 breaker

• Open Status of Incoming-2 breaker

The following points shall be checked before the circuit breaker close command is issued to the incoming breaker.

• Incoming-1 Breaker Open Status

• Incoming-2 Breaker Open Status

• 13.8kV Bus Voltage is zero

• 13.8kV Incoming line is energized/active

• No bus protection function is active

This interlock shall prevent the closing of breaker under a bus fault condition. Additionally, this interlock shall ensure the bus is deenergized prior to closing onto either incoming line.

8.2. INTERLOCKING BETWEEN OUTGOING FEEDERS

Logical interlocks shall be implemented between the outgoing SEL-751 relays to prevent both outgoing lines from being tied together at the existing DMAFB Switchgear bus. The following inputs shall be hardwired to maintain this logic.

• Outgoing-1 Breaker Open Status

• Outgoing-2 Breaker Open Status

• 13.8kV Bus Voltage is energized/active

• No bus protection function is active

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9. COMMUNICATIONS

For security concerns, no communications are allowed to enter or exit the DMAFB substation. Any and all communication provisions on any new devices shall be deactivated and/or left unplugged. DMAFB IT has specifically banned communications leaving DMAFB substation.