Frankfurt (Germany), 6-9 June 2011 Detailed Analysis of the Impact of Distributed Generation and...

Frankfurt (Germany), 6-9 June 2011

Detailed Analysis of the Impact of

Distributed Generation and Active

Network Management on Network

Protection Systems

Federico Coffele

University of Strathclyde (UK)[email protected]

RIF Session 3 – Paper 0428


Federico Coffele – UK– RIF Session 3 – Paper 0428 Slide N. 2

Overview

Test Case Network

Protection System

Simulated Scenarios

Analysis Methodology

Findings

Conclusions

Future Work


Test Case Network

United Kingdom Generic Distribution Network (UKGDS) HV Overhead Type A Network.

The high-level characteristics of this model are as follows:

rural arealong circuit lengthlow customer densityoverhead constructionradial topologylarge overall size

CBT1-11

CBT1-33

CBT2-11

CBT2-33B33kV

B11kV

SpurA1

SpurA2

SpurA3

SpurA4

SpurA5

SpurA6

SpurA7

SpurA8

SpurA9

SpurA10

SpurB1

SpurB2

SpurB3

SpurB4

SpurB5

SpurC3

SpurC4

SpurC1

SpurC2

R-A R-B R-C

PMAR-A

PMAR-B PMAR-C

Feed

er A

Feed

er B

Feed

er C



Protection System


0.10

1.00

10.00

10 100 1000 10000

CBT1-11 & CBT2-11 (1stage): SI, 300 A, TMS 0.2CBT1-11 & CBT2-11 (2stage): SI, 300 A, TMS 0.25CBT1-11 & CBT2-11 DOC: SI, 60 A, TMS 0.1R-A: 400 A, 0.25s DTLPMAR-A: 200 A, 0.1s DTL

sec

A

0,10

1,00

10,00

10 100 1000 10000

CBT1-11 & CBT2-11 (1PH EF 1 stage): SI, 145 A, TMS 0.35

CBT1-11 & CBT2-11 (1PH EF 2 stage): SI, 145 A, TMS 0.4

CBT1-11 & CBT2-11 (SEF): 21 A, 7s DTL

CB-A: 30 A, 0.25s DTL

CB-A (SEF): 21 A, 5s DTL

PMAR-A: 30 A, 0.1s DTL

PMAR-A (SEF)

A

sec


Simulated Scenarios

Types of DG:Inverter interfaced generators (e.g. photovoltaic generation, electric vehicle to grid, etc.)Synchronous and induction (e.g. combined heat and power (CHP), biomass, landfill, wind generators, etc.)

The overall level of DG penetration has been simulated from zero up to a combined total capacity equal to 100% of the network load capacity in steps of 5%.

Network automation:

Further scenarios have been added to reflect changes in the topology of the network, i.e. closing and shifting the positions of normally open points (NOP).



Methodology


Scenarios

Faults

Fault currentscalculation

Protection system response calculation

Protectionsystem data

Performance analysis

Protectionrequirements


Findings

The following protection problems have been investigated by the protection

performance analysis:

Sympathetic tripping

Overload tripping

Blinding

Grading degradation

Beside to the investigation of the problems, possible solutions have been analysed and there advantages/disadvantages have been evaluated.



Sympathetic tripping Sympathetic tripping may occur when the contribution of DG lead to a situation where

non-directional overcurrent relays mal-operate at the same time as, or before, protection on the faulted zone.

Considering the test case network with DLT protection, the incidence of sympathetic tripping due to synchronous DG is:


0

2

4

6

8

10

12

14

16

0 10 20 30 40 50 60 70 80 90 100

Inci

denc

e of

Sym

path

etic

Trip

ping

(%)

Synchronous DG penetration (%)


Solution Directional overcurrent protection?

It works but it is an expensive solution!

IDMT protection instead of DTL protection:It works and it is a cheap solution.


0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

0 10 20 30 40 50 60 70 80 90 100

Inci

denc

e of

Sym

path

etic

Trip

ping

(%)

Synchronous DG penetration (%)


Overload tripping

Overload tripping may occur if DG interface protection operates (either correctly or incorrectly) and results in the addition of previously “hidden” load.

This was observed in the scenarios where DG penetration exceeded 55% and network automation was available to reconfigure the network after a permanent fault.


SpurA1

SpurA2

SpurA3

SpurA4

SpurA5

SpurA6

SpurA7

SpurA8

SpurA9 SpurA10

SpurB1

SpurB2

SpurB3

SpurB4

SpurB5

R-A R-B

PMAR-A

PMAR-B

S2

S3

S4

S5

B11kV

SpurC3

SpurC4

SpurC1

SpurC2

R-C

PMAR-C

Feed

er C

NOP

NOP

Permanent fault

S3

NOP

Fault


Protection grading degradation

When the network topology is changed, the protection grading between OCRs might not be valid anymore.

Considering this specific case, PMAR-B tripping is unnecessary and could cause disconnection of several customers and 2 DG units.


SpurA1

SpurA2

SpurA3

SpurA4

SpurA5

SpurA6

SpurA7

SpurA8

SpurA9 SpurA10

SpurB1

SpurB2

SpurB3

SpurB4

SpurB5

R-A R-B

PMAR-A

PMAR-B

S2

S3

S4

S5

B11kV

SpurC3

SpurC4

SpurC1

SpurC2

R-C

PMAR-C

Feed

er C

NOP

NOP

Permanent fault

S3

NOP

Fault


Solution One very attractive solution is to implement an adaptive overcurrent protection

system.

The protection system is composed of:

New overcurrent relays

Adaptive protection controller

The adaptive protection controller monitors the distribution network and amend the protection settings to optimize the performance of the protection system.


CBT1-11

CBT1-33

CBT2-11

CBT2-33B33kV

B11kV

SpurA1

SpurA2

SpurA3

SpurA4

SpurA5

SpurA6

SpurA7

SpurA8

SpurA9 SpurA10

SpurB1

SpurB2

SpurB3

SpurB4

SpurB5

SpurC3

SpurC4

SpurC1

SpurC2

R-A R-B R-C

PMAR-A

PMAR-B PMAR-C

Feed

er A

Feed

er B

Feed

er C

NOP

NOP


Conclusions Considering a typical UK distribution network the simulation

outcomes show that the protection systems can mal-operate.

Solutions to the discussed problems are:

Sympathetic tripping can be avoided with correct protection settings.

Overload tripping due to false tripping of generator interface protections can be avoided improving the generator interface protection

Protection grading degradation can be solved implementing an adaptive overcurrent protection system.



Future work

Simulation of the UKGDS model and network automation within RTDS.

Implementation of the protection system with commercial IED.

Demonstration of the protection problems and further analysis.

Development and testing of the proposed solutions.


Protection IEDs

Substation Gateway

HMI

LAN Interface

D&A Interface

RTDS

Frankfurt (Germany), 6-9 June 2011 Detailed Analysis of the Impact of Distributed Generation and...

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