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Power System Simulation Lab (Experiment No: Six) Relay Co-ordination for a Sample Distribution System (radial)

System Details: 5 Buses, 4 transmission line section, a Generator and 4relays (IDMT-directional)

The relay make is as follow s Relay rated current = 5 Amps Plug setting = 50% to 250% in steps of 25% Time setting multiplier = 0.05 to 1.0 in steps of 0.01 Relay details

Relay Name R1 R2 R3 R4Primary Rating (1,2,3,4) 800 400 200 100Secondary Rating 5 5 5 5Load Current 800 400 200 100Relay type 3sec 3sec 3sec 3sec

Transmission line details on 100 MVA base: Bus - code Impedance Zpq Line charging

p-q Zpq Y'pq/21-2 0.00 + j0.1 02-3 0.00 + j0.1 03-4 0.00 + j0.1 04-5 0.00 + j0.1 0

Generator Details : G1 = 100 MVA, 11kV Maximum fault level = 1000 MVA. Interpretation according to MiPower :

Observe transmission line details. You find that all lines have similar parameters. Therefore no. oftransmission line libraries = 1

No of generator libraries = 1 As all the relays are of 3 sec type, no of relay libraries = 1

Procedure to enter the data for performing studies using MiPower.

MiPower - Database Configuration Open power system network editor. Select menu option Database Configure . Configure Database dialog is popped up as shown below. Click Browse button.

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Procedure to Draw Relay Click on Directional IDMT Relay icon provided on tool bar or from main menu select

Power system Relays Directional IDMT Put it on the transmission line as shown below

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Then hold ctrl and click on Bus 1, which invokes database manager

Select menu option Libraries Protection Relay Database Points to Note: Relay rated current = 5 Amps Current setting Max = 250 % of % 5 amps = 2.5 x 5 = 12.5 Min = 50 % of % 5 amps = 0.5 x 5 = 2.5 Uniform variation step = 0.25

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Enter time dial setting as below

Time setting multiplier = 0.05 to 1.0 in steps of 0.01 Relay Element Details From main menu select Element Relays Over Current Relay Click “ADD “button And enter the details

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Enter all the four relays details. Click on To Network button which takes control to Network Editor. Executing Over Current Relay Co - ordination Select the menu option Solve Over Current Relay Co-ordination

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The relay co - ordination will be executed. Go to graph and plot Current in X - axis and Time in Y - Axis.

Inference: