Modelling & Simulation of Transmission Line Auto-reclose Scheme Using Matlab/Simulink

1MUHD HAFIZI IDRIS1SURYA HARDI

2MOHD ZAMRI HASAN1SYAFRUDDIN HASAN

1INDRA NISJA1NOR HANISAH BAHARUDIN

1School of Electrical System Engineering & 2Faculty of Engineering Technology

Universiti Malaysia Perlis

Introduction Auto-reclose (A/R) relay is one of important protection relays

installed at the transmission line. It is used to re-energize the line back to operation after been

tripped by main protection relay. Most of fault occurrences at transmission line are transient in

nature and only small percentage was due to permanent fault. Some of transient fault causes are lightning strike on phase

line, momentary contact between foreign object and phase line, momentary clashing of phase conductors etc.

Auto-reclose relay can be classified into two categories which are single-shot and multi-shot schemes.

In single-shot auto-reclose, only one reclose attempt will be made for any fault occurrence. In this category, the breaker will be tripped and locked out for the case of permanent fault or evolving fault during reclaim time.

Introduction The application of auto-reclose relay along with main

protection relay is different for different level of voltage at transmission line.

All three phases of the line might be tripped and reclosed together at the same time even though fault occurred at only one phase of the line.

In this research, SimPowerSystems toolbox inside Matlab/Simulink package was used to model and simulate transmission line, equivalent sources, load, over-current relay and auto-reclose relay.

The model can be used to increase the understanding on auto-reclose scheme especially in transmission line network system.

MATLAB is a software which is suitable for technical computation. It can compute, visualizes, and program the mathematical equations in an easy way and easy to be understood. It also has many ready built block-sets for power system studies (Simulink package).

Project Scopes Auto-reclose scheme is one of protection scheme which is

complex and difficult to be understood because it requires many parameters and conditions to be fulfilled before any decision can be made.

In this research, several limitations were applied to ease the process of modelling and simulation. The scopes are as follows: Single Line-to-ground Fault Definite Time Over-current Relay Faults in the Line Length Single-shot Auto-reclose Three-pole Auto-reclose Synchronism Checking – all conditions of synchronism are

assumed fulfilled. Breaker status and breaker ready conditions are assumed

fulfilled.

Modeling & SimulationModeling Parameters & Relay

Settings

Modeling & SimulationModeling Parameters & Relay

Settings

Modeling & SimulationSubstations, transmission line, load and measurements

subsystem

Remote Breaker

Modeling & SimulationDefinite time over-current

relay

Modeling & SimulationAuto-reclose relay subsystem

Modeling & SimulationOverall model of auto-reclose

scheme

Simulation Results A fault was initiated from 0.06 s until 0.12 s at 10 km from

local substation.

Local red phase current

(A)

Local rms red phase current

(A)

Simulation Results

Local red phase-to-

ground voltage (V)

Local rms red phase-to-

ground voltage (V)

Simulation Results From all Figures, after normal condition, fault was detected at around

0.071 s when fault current higher than pickup current (Ipickup = 345.6 A) but breaker was not trip yet.

It can be seen that current became very high from nominal current while voltage dropped from nominal voltage during fault condition.

After fault was detected, timer of 0.5 s of local definite time over-current relay was started and trip signal was sent to local circuit breaker at around 0.582 s and line current became zero due to open circuit.

Voltage became zero as circuit breakers at both substations were tripped at the same time.

At the same time of trip signal sent, a signal was sent to auto-reclose relay to initiate/start auto-reclose relay.

The dead time of 1.0 s for local auto-reclose relay was started and running until around 1.58 s and local circuit breaker was reclosed.

The current still zero because remote circuit breaker didn’t reclosed yet.

Simulation Results After local breaker reclosed, voltage at local substation

back to normal but slightly higher than nominal voltage (equal to busbar voltage).

At around 2.076 s, remote breaker was reclosed after remote auto-reclose relay dead time of 1.5 s had been elapsed.

Remote breaker successfully reclosed after all conditions for remote auto-reclose relay such as breaker in open condition, closing coil ready, initiate/start signal from over-current relay received and synchronism between line and busbar voltage were achieved.

It can be seen that after both breakers from local and remote substations successfully reclosed, current and voltage back to nominal value.

Conclusions Auto-reclose scheme was successfully modelled and simulated

using Matlab/Simulink software. From the result, the waveforms produced show the capability

of Matlab/Simulink software in modelling and simulating power system protection scheme even for complex protection scheme such as auto-reclose scheme.

In the designed Simulink model, some limitations and assumptions were applied to ease the modelling because the aim of this research is for educational purpose and the important thing is the waveforms produced are as expected and similar to results produced by dedicated protection system software.

However, the limitations and project scopes can be further modelled in the future to simulate actual scheme applied in transmission substations.

References[1] Paul M. Anderson. 1998. Power System Protection. Wiley.

[2] Bhavesh Bhalja, R. P. Maheshwari, Nilesh G. Chothani. 2011 Protection and Swithgear, Oxford University Press.

[3] Abdul Halim Abu Bakar & Shinichi Imai. 2002. Auto-reclose Performance on 275 kV and 132 kV Transmission Line in Malaysia. Transmission and Distribution Conference and Exhibition. Page(s): 603 - 608 vol.1

[4] M. Jannati, B. Vahidi, S.H. Hosseinian, S.M. Ahadi. 2011. A novel approach to adaptive single phase auto-reclosing scheme for EHV transmission lines. Electrical Power and Energy Systems. Vol. 33. Pp. 639–646.

[5] Yeshwant G. Paithankar. 1997. Transmission Network Protection: Theory and Practice. Power Engineering (Willis), CRC Press.

[6] Network Protection and Automation Guide. Protective Relays, Measurement and Control. Alstom Grid. 2011.

[7] Viktor Perelmuter. 2012. Electrotechnical Systems: Simulation with Simulink® and SimPowerSystems. CRC Press.

[8] Matlab Getting Started Guide. R2011b. MathWorks. 2011.

Thank You