Substation Data Integration&

Information Exchange

Advisor: Dr. Mladen Kezunovic

Student: Sasa Jakovljevic

Texas A&M University, Department of Electrical Engineering, College Station, Texas, USA

Project objective:Utilize data obtained from Intelligent Electronic Devices (IEDs) to enhance Power System State

Estimation

Analyze digital relays and other Intelligent Electronic Devices installed in substations

Explore modern trends in substation communications (IEC 61850)

Collect data from various locations within substation and adjust the format

Provide redundancy of measurements Write an application for data processing and

consistency checking Communicate output to the higher level

Concentrate on the following issues:

Research Approach

Substation Layout - One Line Representation

350 kV

TR56

L S311

CB31

S301

CB32

S302

S303

S304

S313

TL51

CB33

S305

CB34

S306

S307

S308

CB35

S309

S310

S314

TL52

S312

TL54

n

b

Node Number

Branch Number

SUBSTATION LAYOUT

CB - Circuit BreakerS - SwitchTL - Transmission LineTR - Transformer

1

1

2

3

4

56

7 8

9

2

3

7

4

5

8

6

9

A

A

A

A

A

A

A

A

A

A

AkVkW

kVAr

AkVkW

kVAr

kV

kV

AkVkW

kVAr

AkVkW

kVAr

AkVkW

kVAr

10

10

S315

L - Load

Modeling Issues

Power Apparatus: Circuit Breakers Disconnect Switches Busbars Load - Reactor

Analog Measurements: Currents [A] Voltages [kV] Power Flows [kW, kVAr] Power Injections [same]

Digital Measurements: CB Statuses DS Statuses Ground Switches

Three-phase Substation Model in SIMULINK

Processing Algorithms in MATLABStart

Node number

Node classificationbusbar or internal node ?

I KCLcannot be performed

End

I KCL sattisfiedI KCL

NOT sattisfied !

Collect all incident branches(and appropriate orientations)

All incident brancheshave current measurement ?

Sum the currents in incident branches(consider correct orientations)

Sum of phase A currents < KCLerr&

Sum of phase B currents < KCLerr&

Sum of phase C currents < KCLerr

I KLCnot performed for

external node

Yes

Yes

Yes

No

No

No

Start

Branch number

Status = closed&

Current <> 0

Find appropriate branch currentand branch status

End

Status = open&

Current = 0

Status = open&

Current <> 0

Status = closed&

Current = 0

No

No

No

ConsistencyOK

ConsistencyOK

NOconsistency !

Status changedto unknown

LOWcurrent value !

Status changedto unknown

Consistencycannot beperformed

due tostatus

unknown

Yes

Yes

Yes

Yes

No

Start

Branch number

Number ofswitching elements = 3 ?

Switch1 = closed&

Circuit Breaker = closed&

Switch2 = closed

End

Count switching elementsin the branch

Circuit Breaker = closed&

(Switch1 or Switch2) = open

Yes

Yes

No

Yes

No

No

Branch statusequals

switch statusBranch status

closed

Branch statusunknown

Branch statusopen

Start

Branch number

Branch with double currentmeasurements ?

abs(IA1-IA2)<MADMdis * max(abs(IA1),abs(IA2))&

abs(IB1-IB2)<MADMdis * max(abs(IB1),abs(IB2))&

abs(IC1-IC2)<MADMdis * max(abs(IC1),abs(IC2))

Non consistentmeasurements !

1AA II 2

21 AAA

III

End

Consistentmeasurements

No redundantmeasurements

Yes

Yes

No

No

Topology Checking

RedundantCurrents

Kirchoff’sCurrent

Law

BranchStatus

Output Tables

Project Results - Future Work

Node # 1 2 3 4 5 …

Voltage (mag) 0.99206 0.99206 0.99206 0.99206 0.99207

Voltage (ang) 0.208 0.208 0.207 0.207 0.208

Injection (act) n/a -0.0235 n/a n/a n/a

Injection (react) n/a -0.9814 n/a n/a n/a

Branch # 1 2 3 4 5 …

Current (mag) 1.62494 1.02758 2.59226 1.42991 1.95869

Current (ang) 176.539 -158.331 -173.769 179.742 -2.489

Flow (act) - - -2.55749 - -3.35952

Flow (react) - - -0.26988 - -0.10291

Status 1 1 1 1 1

Communicated Data: Three-phase or single-phase output Possible errors filtered out More reliable data

Future Work: Substation transition analysis Switching sequences & interlocking State tracking & predicting Writing user friendly software

Node Table

Branch Table