Application Note Circuit Breaker Tests

AN CP0504 Application Note

BASIC CIRCUIT BREAKER TESTS USING CPC 100


Manual Version: ANCP0504.AE.1 © OMICRON electronics 2005. All rights reserved. This Application Note is a publication of OMICRON electronics GmbH. All rights including translation reserved. Reproduction of any kind, e.g., photocopying, microfilming or storage in electronic data processing systems, requires the explicit consent of OMICRON electronics. Reprinting, wholly or in part, is not permitted. This Application Note represents the technical status at the time of printing. The product information, specifications, and all technical data contained within this Application Note are not contractually binding. OMICRON electronics reserves the right to make changes at any time to the technology and/or configuration without announcement. OMICRON electronics is not to be held liable for statements and declarations given in this Application Note. The user is responsible for every application described in this Application Note and its results. OMICRON electronics explicitly exonerates itself from all liability for mistakes in this document.

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Contents

Contents 1

Using This Document . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4 1.1 Operator Qualifications and Safety Standards . . . . . . . . . . . . . . . . . . . . .4 1.2 Safety Measures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5 1.3 Conventions and Symbols Used . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5 1.4 Related Documents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5

2

Basic Circuit Breaker Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6 2.1 Testing an Overcurrent Relay with ARC Function. . . . . . . . . . . . . . . . . . .6 2.2 Testing an Overcurrent Relay with ARC Function and Measuring the CB Opening/Closing Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9 2.3 Measuring the CB Opening Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12 2.4 Measuring the CB Closing Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14

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1 Using This Document This Application Note provides you with detailed information on how to measure the touch voltage according to the VDE 0101/CENELEC HD 637 S1:1999 and IEEE 80-2000, 81-1983 and 81.2-1991 international standards safely, properly and efficiently. The AN CP0504 Application Note describes the touch voltage measurement using the OMICRON electronics measurement setup consisting of the CPC 100 test system, the CP CU1 coupling unit and the CP GB1 grounding box. Reading the AN CP0504 Application Note alone does not release you from the duty of complying with all national and international safety regulations relevant to working with CPC 100 and CP CU1. The regulation EN 50191 "The Erection and Operation of Electrical Test Equipment" as well as all the applicable regulations for accident prevention in the country and at the site of operation has to be fulfilled.

1.1 Operator Qualifications and Safety Standards Working on overhead lines is extremely dangerous. The touch voltage measurement described in this Application Note must be carried out only by qualified, skilled and authorized personnel. Before starting to work, clearly establish the responsibilities. Personnel receiving training, instructions, directions, or education on the measurement setup must be under constant supervision of an experienced operator while working with the equipment. The touch voltage measurement must comply with the relevant national and international safety standards listed below: •

EN 50191 (VDE 0104) "Erection and Operation of Electrical Equipment"

•

EN 50110-1 (VDE 0105 Part 100) "Operation of Electrical Installations"

•

IEEE 510 "IEEE Recommended Practices for Safety in High-Voltage and High-Power Testing"

•

LAPG 1710.6 NASA "Electrical Safety"

Moreover, additional relevant laws and internal safety standards have to be followed.

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Using This Document

1.2 Safety Measures Before starting a measurement, read the safety rules in the CPC 100 User/Reference Manual and CP CU1 Reference Manual carefully and observe the application specific safety instructions in this Application Note when performing measurements to protect yourself from high-voltage hazards.

1.3 Conventions and Symbols Used In this document, the following symbols indicate paragraphs with special safety relevant meaning:

Symbol

Description Equipment damage or loss of data possible. Personal injury or severe damage to objects possible.

1.4 Related Documents The following documents complete the information covered in the AN CP0504 Application Note:

Title

Description

CPC 100 User Manual

Contains information on how to use the CPC 100 test system and relevant safety instructions.

CPC 100 Reference Manual

Contains detailed hardware and software information on CPC 100 including relevant safety instructions.

CP CU1 Reference Manual

Contains information on CP CU1 and CP GB1 and provides typical application examples.

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2 Basic Circuit Breaker Tests 2.1 Testing an Overcurrent Relay with ARC Function This sequence of four states tests a complete autoreclosure cycle with both a short dead time (rapid autoreclosure) and a long dead time (slow autoreclosure). Figure 2-1: Setup for testing an overcurrent relay with autoreclosure function

I> OFF

ON

OFF

6

ON

Basic Circuit Breaker Tests

Figure 2-2: Sequencer test card with parameters and measurements of the four states

State 1: "wait for the CB to open" Set to output 400A until the trigger condition "Overload" occurs. Here, trigger condition "Overload" means: CPC 100 cannot provide the 400A any longer because of the opening CB contact. Therefore, the opening CB contact terminates state 1. The measurement table shows for state 1 that the relay time + the CB opening time lasted 290ms. State 2: "wait for the CB to close" Short dead time. Set to output 50A until the "Overload" trigger condition that started state 2 clears. The measurement table shows for state 2 that the short dead time + the CB closing time lasted 477ms. This time also includes the additional time to compensate for the debounce (see note below).

State 4: "wait for the CB to close"

The actual value for CB close equals 477ms - 100ms = 377ms.

Long dead time. Set to output 50A1 until the "Overload" trigger condition that started state 4 clears.

Note that the r.m.s. measurement of IOut reacts slow and therefore the measurement table does not show the full current.

The measurement table shows for state 4 that the long dead time + the CB closing time lasted 3.1910s. This time also includes the additional time to compensate for the debounce (see note below).

State 3: "wait for the CB to open"

The actual value for CB close equals 3.1910s - 100ms = 3.0910s.

Like state 1.

1

)

Not relevant for this test.

Current values < 50A do not initiate an "Overload" when the current circuit opens. For this reason, a nominal current value of 50A was chosen here, even though the CB is open.

Note:

For debouncing purposes, at CB closing time measurements, CPC 100 adds a fixed time of 100ms to the measured value. In order to determine the true CB closing time value, these 100ms need to be deducted from the value displayed in the measurement table.

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Time sequence of the four states Figure 2-3: Time sequence of the four states to test the autoreclosure cycle

fault inception: overcurrent condition occurs

I

CB opens

CB autoreclosure CB opens again

100ms

state 1

*)

8

state 2 *) short dead time

100ms

state 3

state 4 *) long dead time

t

States 2 and 4 include the additional 100ms CPC 100 adds to compensate for the debounce (see note above).


2.2 Testing an Overcurrent Relay with ARC Function and Measuring the CB Opening/Closing Time This sequence of four states tests an autoreclosure cycle with a short relay dead time as well as the CB opening and closing times. Figure 2-4: Setup for testing an autoreclosure cycle with a short relay dead time as well as the CB opening and closing times

I> OFF

ON

ON

OFF

*

* = Diodes to decouple the relay’s auxiliary contacts ON/OFF from each other.

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Figure 2-5: Sequencer test card with parameters and measurements of the four states

State 1: "wait for open command" Set to output 400A until the trigger condition "Binary" occurs. Here, trigger condition "Binary" means: the overcurrent relay’s auxiliary contact that activates the CB OFF coil closes. This terminates state 1 and starts state 2. The measurement table shows for state 1 that 233ms after the fault inception the auxiliary contact for the OFF coil closed. State 2: "wait for the CB to open" Set to output 400A until the "Overload" trigger condition occurs. Here, trigger condition "Overload" means: CPC 100 cannot provide the 400A any longer because of the opening CB. Therefore, the opening CB represents the "Overload" trigger, terminates state 2 and starts state 3. The measurement table shows for state 2 that 57ms after it started the CB opened. This time represents the actual CB opening time. State 3: "wait for close command" Set to output 50A1 until the trigger condition "Binary" occurs. Here, trigger condition "Binary" means: the overcurrent relay’s auxiliary contact that activates the CB ON coil closes. This terminates state 3 and starts state 4. The measurement table shows for state 3 that 320ms after it started, the auxiliary contact for the ON coil closed.

1

10


State 4: "wait for the CB to close" Set to output 100A until the "Overload" trigger condition occurs. Here, trigger condition "Overload" means: due to the closing CB, CPC 100 is able to provide the 100A. This is regarded a "clearing overload situation". Therefore, the closing CB represents the "Overload" trigger and terminates state 4. The measurement table shows for state 4 that the overload cleared 163ms after state 4 started. Note: This time does not represent the actual CB closing time. It also includes the additional time to compensate for the debounce (see note below). Therefore, in this example the real value of the CB closing time equals 163ms - 100ms = 63ms. Note that the r.m.s. measurement of IOut reacts slow and therefore the measurement table does not show the full current.



)

Note:


Time sequence of the four states Figure 2-6: Time sequence of the four states to test an autoreclosure cycle with a short relay dead time as well as the CB opening and closing times

fault inception: overcurrent condition occurs

auxiliary contact for the CB OFF coil closes. CB opens

I

auxiliary contact for the CB ON coil closes

CB closes

100ms

t state 1

*)

state 2

state 3

state 4 *)

State 4 includes the additional 100ms CPC 100 adds to compensate for the debounce (see note above).

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2.3 Measuring the CB Opening Time This sequence of two states measures the CB opening time, i.e., the time it takes for the circuit breaker to open after a trip command was issued. To do so, the CB coil "OFF" is activated by a switch that, at the same time, is wired to CPC 100’s binary input BinIn to act as a trigger signal (refer to figure 2-8). Figure 2-7: Setup for measuring a circuit breaker’s opening time

OFF

12


Figure 2-8: Sequencer test card with parameters and measurements of the two states

State 1: "wait for open command" Set to output 400A until the trigger condition "Binary" occurs. Here, trigger condition "Binary" means: the switch to activate the CB coil is pressed. This switch is wired to CPC 100’s binary input BinIn, i.e., pressing the switch within the set 30s of time represents the "Binary" trigger and terminates state 1. The measurement table shows for state 1 that the switch was pressed 2.3s after the state began, i.e., after CPC 100’s "test start/stop" pushbutton was pressed.


Since the CB was still closed during that time, a current was output. State 2: "wait for CB to open" Set to output 400A until the trigger condition "Overload" occurs. Here, trigger condition "Overload" means: CPC 100 cannot provide the 400A any longer because of the opening CB. Therefore, the opening CB represents the "Overload" trigger and terminates state 2. The measurement table shows for state 2 that the CB opened 57ms after state 2 started. This time represents the actual CB opening time.

Time sequence of the two states: Figure 2-9: Time sequence of the two states to test a circuit breaker’s opening time

I

Switch to activate the CB coil is pressed ("Binary" trigger).

CB is open ("Overload" trigger).

t state 1

state 2

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2.4 Measuring the CB Closing Time This sequence of two states measures the CB closing time, i.e., the time it takes for the circuit breaker to close after a trip command was issued. To do so, the CB coil "ON" is activated by a switch that, at the same time, is wired to CPC 100’s binary input BinIn to act as a trigger signal (refer to figure 11). Figure 2-10: Setup for measuring a circuit breaker’s closing time

ON

14


Figure 11: Sequencer test card with parameters and measurements of the two states

State 1: "wait for close command" Set to output 50A1 until the trigger condition "Binary" occurs. Here, trigger condition "Binary" means: the switch to activate the CB coil is pressed. This switch is wired to CPC 100’s binary input BinIn, i.e., pressing the switch within the set 30s of time represents the "Binary" trigger and terminates state 1. The measurement table shows for state 1 that the switch was pressed 1.7s after the state began, i.e., after CPC 100’s "test start/stop" pushbutton was pressed.


Since the CB was open during that time, no current was output. State 2: "wait for CB to close" Set to output 100A until the trigger condition "Overload" occurs. Here, trigger condition "Overload" means: due to the closing CB, CPC 100 is able to provide the 100A. This is regarded a "clearing overload situation". Therefore, the closing CB represents the "Overload" trigger and terminates state 2. The measurement table shows for state 2 that the overload cleared 163ms after state 2 started. This time, however, does not represent the actual CB closing time. It also includes the additional time to compensate for the debounce (see note below). Therefore, in this example the real value of the CB closing time equals 163ms - 100ms = 63ms. Note that the r.m.s. measurement of IOut reacts slow and therefore the measurement table does not show the full current.

1

)


Note:


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Time sequence of the two states: Figure 12: Time sequence of the two states to test a circuit breaker’s closing time

CB is closed ("Overload" trigger).

I

100ms

Switch to activate the CB coil is pressed ("Binary" trigger).

t state 1

*)

16

state 2 *)

State 2 includes the additional 100ms CPC 100 adds to compensate for the debounce (see note above).

Application Note Circuit Breaker Tests

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