Can Your Circuit Breaker Test Device Do This?

May 7, 2021

Easily test breakers of all voltage levels

More than 1000 customers on five continents enjoy the many benefits of the CIBANO 500. The device allows to efficiently perform all the important circuit breaker measurements, such as timing, static and dynamic contact resistance, travel, coil current, or motor current - on breakers of all voltage levels. Its extensive capabilities and efficient test methods for testing high voltage breakers are widely known. What is more, with its internal voltage/current source it can also verify breaker performance during special conditions, such as overvoltage, undervoltage or low DC supply.

In this article, we show you what CIBANO 500 can do for you in testing medium or low voltage breakers that other test devices cannot. CIBANO 500 is a device that can conveniently test breakers without a close coil and verify the under-voltage release function or the overcurrent release function of your breakers.

What is an undervoltage release function? In addition to the common trip and close coils, some breakers also include an undervoltage coil. An undervoltage coil is a coil which is usually included in breakers located in a substation which does not have a backup power system, or where the voltage is not supervised. The purpose of this undervoltage coil is twofold: the first purpose is to trip the breaker if the supply voltage goes below a certain threshold (see IEC 62271-1:2017), and the second is to prevent the breaker from reclosing while the voltage level stays below a certain level.

CIBANO 500s under-voltage release test will determine the voltage level when the under-voltage coil will trip the breaker. With the internal voltage source included in CIBANO 500, it is very simple to perform this test. With the breaker in Open position, CIBANO 500 starts the test by supplying the undervoltage coil with its nominal voltage, after which it closes the breaker and then starts to decrease the supply voltage for the undervoltage coil in steps until the breaker trips.

The overcurrent release (coil) is a coil which is normally included in very simple breakers which are placed in substations without station battery. With these breakers, the protection relay is normally supplied from the secondary side of a CT. The protection relay supervises the current from the CT and when the current goes over a certain threshold, it sends/forwards a command to the overcurrent coil and the overcurrent coil will trip the breaker.

As for Minimum Pick-up test the Overcurrent Release test is using the internal source of CIBANO 500. Configured as current source, CIBANO 500 internally can create a pulse ramp and ramp up the current until the overcurrent coil trips the breaker.

Most breakers which are equipped with overcurrent release (coil) are very simple in design and only have a trip coil, but normally lack a close coil. Thus, what needs to be done when the breaker is tripping is that the operator must go to the breaker and manually close it again. That means that traditional time measurement is not possible. But how can such a breaker conveniently be tested? CIBANO 500s answer is motion-based timing measurement were the travel curve is used as reference for timing calculation.

By creating a longer timing test, to have time to close the breaker manually, the status of the main contacts and travel are measured. With the motion-based timing feature the zero point is then moved to the start of the travel curve and thus allows to use this point in time as a reference for calculating the closing time.

If you want to know more about the tests for these functions, have a look below where you can find a paper on the corresponding tests or simply watch the corresponding video!

Read the Paper