POWER SYSTEM STUDIES

www.koncar-institut.com

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| KONČAR Power System Studies

Specific areas that we cover with our experts are:

Power system studies:

KONČAR – Electrical Engineering Institute, Inc. and its partner Institutions offer studies related to power systems and transformers. They include feasibility studies, engineering analysis, verification of the existing studies, consulting, fault analysis, etc.Extensive experience of the KONČAR – Electrical Engineering Institute, Inc. and its partners in power en-gineering meets all the requirements of the nowadays state of the art power system studies. Offered areas cover all stationary and transient studies related to power systems. Numerous references of our expert engineers are available upon your request.

Overview

Areas of expertise

Types of expert studies

» Transformers » Phase shifters » Static var compensators » Variable shunt reactors » HVDC technologies » Gas insulated substations » Air insulated substations » Overhead lines

» Cables » Thermal power plants » Hydro power plants » Wind and solar power plants » Electric railways » Arc-furnaces » Emitted electromagnetic field levels

» Load flow » Short circuit » Switching transients » Lightning transients » Grounding system analysis » Cable sizing » Motor starting » Fault analysis » 3D FEM analysis » Overvoltages and insulation coordination » Power quality (unbalance, flicker and harmonic analysis) » Calculation of electric and magnetic fields around power system objects (substations, transmission lines, cables, power plants, etc.)

» Analysis of electromagnetic interference caused by a HV transmission network on buried pipelines & communication cables

» Dimensioning of compensators (SVC), network frequency response and dimensioning of harmonic filters

» Reactive power compensation in transmission networks

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To conduct studies, we are using the following software in collaboration with our partner Institutions:

» EMTP-RV » EMTP-ATP » NEPLAN » ETAP » PSS/E » DIgSILENT » Simulink » Infolytica Suite (MagNet, ElecNet, ThermNet) » Ansys EM suite (Maxwell, HFSS) » EFC-400

Transients recorded by monitoring system in case of a lightning strike to the 220 kV overhead line. The recorded signal is taken from the Končar’s transformer monitoring system TMS+ and it shows how the overvoltage is transmitted through an au-totransformer.

Available software

Transient studiesMeasured frequency dependent admittance matrix of a power transformer. It is used to create a black box transformer model in EMTP-RV. This model can be used for switching and lightning studies, to calculate the voltages transmitted through a trans-former.

Lightning strike to the overhead line simulated in EMTP-RV with detailed transformer model. The model is used to calculate the amplitude of the transmitted overvoltages through a power transformer.

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28-250

-200

-150

-100

-50

0

50

100

150

200

t (ms)

U (k

V)

A (HV) B (HV) C (HV) A (LV) B (LV) C (LV)

Span

Transformer

Cable network

Lighting strike

Power network

Tower grounding resistance

Tower model

| KONČAR Power System Studies

Shunt reactorSF6 circuit breaker

Transmission network

Surge arrester

Busbar

+1uH

+0.5

+1uH

+0.5

+0.5nF

+

C230.05nF

+0.5nF

+1uH

+0.5

+1uH

+0.5

+0.5nF

+

C260.05nF

+0.5nF

+1uH

+0.5

+1uH

+0.5

+0.5nF

+

C290.05nF

+0.5nF

Arc model based on Schwarz/Avdonin equation

DEV13

Arc model based on Schwarz/Avdonin equation

DEV14

Arc model based on Schwarz/Avdonin equation

DEV15

Arc model based on Schwarz/Avdonin equation

DEV16

Arc model based on Schwarz/Avdonin equation

DEV17

Arc model based on Schwarz/Avdonin equation

DEV18

ZnO

+

660000 ?vi

ZnO1

+

+ RL5

+

1uF C34

+

AC5?v

+

Data functionL nonlinear

+R

37?i

+R

38?i

+Lnonl13?if

+L2

4?i

+1 2

Tr0_9

1

+1 2

Tr0_10

1

+A

m17?i

VM+?v

m18

VM+?v

m19

VM+?v

m20

+

Lnonl14?if

+

Lnonl15?if

+R

39?i

+R

40?i

+R

41?i

+R

42?i

+

3.8nF C31

+

0.1nF C32

+

0.1nF C33

+L2

5

7.19

+L2

6

7.19

+L2

7

7.19

Data functionZnO

a

b

c

BUS9

c

a

b

BUS10

a

c

b

BUS8

Network model for simulating switching transients of a shunt reactor. Switching of a shunt reactor may cause severe transients such as high inrush currents or overvoltages.

Switching of small inductive currents in the case of de-energization of a shunt reactor leads to switching overvoltages.

Inrush current in the case of energization of a shunt reactor.

Harmonics and short circuit analysisEquivalent scheme of a system for analyzing SVC and filters interaction with the network. The model is used in an iterative procedure to determine the technical characteristic of the filter and to calculate har-monic distortions generated by the SVC operations.

Network

Transformer

Filter 2Filter 1SVC

Frequency (Hz)

Impe

danc

e (o

hm)

0 50

10

20

30

40

50

100 150 200 250 300 350 400

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0 kV19.7 kA

0 kV16.3 kA

0 kV25.6 kA0 kV

35.6 kA0 kV

33.2 kA

0 kV31.8 kA

0 kV40.6 kA

Network 1

Network 2

Generator 1 Generator 2

Generator 3

Motor 1

Motor 2

3D FEM analysis

Model for calculation of short circuit currents in the case of a three-phase fault.

3D FEM core type power transformer model. The model is used to evaluate the stray losses in the transformer’s structural elements and to determine the value of the short circuit impedance of the trans-former.

Magnetic induction calculation for the power transformer model.

Temperature calculation for a power trans-former. The results are used to check the hot spots in a clamping system and to dimension the transformer according to the calculated temperature values.

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KONČAR-Institute-Power System Studies-10-1902

Contact us for more information!www.koncar-institut.com kpss@koncar-institut.hr

Fallerovo šetalište 22Zagreb 10000, Croatia

KONČAR Electrical Engineering Institute, Inc.