codr protection 1

8/22/2019 CoDR Protection 1

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NEPTUNE Power System Protection

Kevin Schneider, Chen-Ching Liu

Department of Electrical Engineering, University of Washington

Harold KirkhamJet Propulsion Laboratories


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Protection Areas

1) Medium voltage backbone

protection

2) Internal node protection

3) Low voltage protection


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Backbone Protection Layers

1st- Differential measurements and pilot

tones, combined.

2nd- Primary zone distance relays.

3rd- Secondary zone distance relays


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Backbone 1st Protection Layer

Uses two protection techniques

1) Differential current protection

2) Pilot tone relaying


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Normal Operating Conditions

Differential current

measurements.

Double pilot tone.

DO NOT TRIP

Primary relay in place. Back up relay in place.

Fiber Tranf er

Path

Current Sensors

Node 1 Node 2

PilotTones


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Loss of Both Signals

Differential comms.

are lost.

Pilot tones are lost.

PRIMARY TRIPS

BREAKER Back up relay in

place.

Fiber Tranf er

Path

Current Sensors

Node 1 Node 2

PilotTones


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Loss of Differential Comms.

Differential comms.

Are lost.

Pilot tones are not lost.

DO NOT TRIP

Primary relay in place.

Back up relay in place.

Fiber Tranf er

Path

Current Sensors

Node 1 Node 2

PilotTones


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Loss of Pilot Tones

Fiber Tranf er

Path

Current Sensors

Node 1 Node 2

PilotTones

Pilot tones are lost.

TRIP IF

DIFFERENTIAL

PROTECTIONDETECTS FAULT

Back up relay in

place.


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Backbone 2nd Protection Layer

Current and Voltage Sensors

Node 1 Node 2

BackboneBackbone Primary Zone


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Backbone 3rd ProtectionLayer

Current and Voltage Sensors

Node 1 Node 2

BackboneBackbone Secondary Zone


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Backbone Relay Coordination

Protective Layer Protective Method Time to Operate

1st Current Differential &

Pilot Tones

ASAP ( 6ms)

2nd Zone 1 Distance 8 ms

3rd Zone 2 Distance 10 ms


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Node Protection Layers

1st- Node differential protection step 1

2nd- Converter differential protection

3rd- Node differential protection step 2

Note: the 1st and 3rd layers work on the same principle but their resulting

protective actions are different.


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NCB

A

B C

D

Fast -OFF switch

E

G H

Essential Loads(Protection, Communications) External Loads

Energy

Storage(Communications)

Converter 1 Converter 2

ProtectionEnergy

Storage(Protection)


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Node 1st Protection Layer

Node 1

BackboneBackbone

Current 1

Current 3

Current 2

Current 1 + Current 2 + Current 3 0

If a fault is detected then the running converter is secured

and the second unit is started


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Node 2nd Layer Protection

Same techniques astransformerdifferential protection

Must account forlosses in the main

power converter

If a fault is detectedthe converter issecured and the otherunit started

Main Power

Converter

Current 1

Current 2


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Node 3rd Layer Protection

Node 1

BackboneBackbone

Current 1

Current 3

Current 2

Current 1 + Current 2 + Current 3

0

Similar to the first layer except that in the event of a fault the entire

node is secured through the opening of adjacent node backbone

breakers


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Node Relay Coordination

Protective Layer Protective Method Time to Operate

1st Node Differential ASAP ( 4msec)

2nd Converter Differential 6 ms

3rd Node Differential 8 ms

Note: all three layers will actuate before the 3rd layer of the backbone

protection. This will prevent unnecessary loss of loads.


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Node Low Voltage Protection

Low voltage protection is similar to

distribution system protection

Can use any of the following methods

1) Over current

2) Distance relaying

3) Ground fault indication

4) A combination of methods


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Questions?

codr protection 1

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