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Test 7ut

This document outlines the test procedure for the Siemens 7UT61 relay using the Omicron CMC256 or 356 test equipment. It describes testing the differential characteristics by injecting balanced currents and gradually increasing them to check the pickup value is within 5% of the set value of 0.2 I/In0. It also tests the two slopes of the tripping characteristic by simulating differential and stabilizing currents to ensure they satisfy the characteristic equations for each branch of the testing.

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113 views1 page

Test 7ut

This document outlines the test procedure for the Siemens 7UT61 relay using the Omicron CMC256 or 356 test equipment. It describes testing the differential characteristics by injecting balanced currents and gradually increasing them to check the pickup value is within 5% of the set value of 0.2 I/In0. It also tests the two slopes of the tripping characteristic by simulating differential and stabilizing currents to ensure they satisfy the characteristic equations for each branch of the testing.

Uploaded by

ashish_2187
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
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Download as PDF, TXT or read online on Scribd
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This is the test procedure for Siemens 7UT61 Relay (IEC61850 supported numerical relay).

Omicron CMC256 or 356 Test Equipment or Any Equivalent To Be Used.

Following parameters define differential characteristics:

Setting in our example

Pickup value of differential current = 0.2 I/In0

Slope 1 of tripping Characteristic = 0.25

Base point for slope 1 of charac = 0

Slope 2 of tripping characteristic = 0.75

Base point for slope 2 of charac = 2.5

I-RESTRAINT for start detection = 0.1 I/In0

Pickup vale of high set trip = 4.0 I/In0

1. Test Procedure for Checking of first branch:

Objective: To test the sensitivity threshold of the differential protection which considers constant error currents such as
magnetizing currents (I-DIFF>).

Test method :

-.Inject balanced currents in all phases. (Below the pickup value for fault detection (I-RESTRAINT).

- Gradually increase currents till relay operation.

- Note down the pickup value.

Pass criteria :

Characteristic equitation for this branch: (Basepoint1) ≤ ISTAB ≤ (IDIFF /m1)

The operating current should be within +/- 5% of set value.

2. Test Procedure for Checking of second branch:

Objective: To check slope m1, this considers current proportional errors result from transformation errors of the main CTs
or the input CTs of the protection relay, mismatching and influence of tap changers in transformers.

Test method: Simulate differential and stabilizing currents such that they lie in the first region over and under the curve.

Stabilizing current ISTAB= │I1│+ │I2│ (Algebraic Summation)

Differential current IDIFF = │I1 + I2│ (Vectorial Summation)

Inject 1 A balanced current in HV and LV windings.

Gradually increase HV current till relay operation. Note down value.

Pass criteria :

Characteristic equation for this branch: (IDIFF /m1) ≤ ISTAB ≤ (1/IDIFF)

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