Replacement of circuit breakers Elektron-E16V 0.4 kV in sections of auxiliary equipment switchgear

IGNALINA NUCLEAR POWER PLANT (INPP)

Complete transformer substations KTP SN 0,5 manufactured by Minsk Electrotechnical Plant named after V. I. Kozlov are used in order to ensure auxiliary power supply for 0.4 kV consumers of Ignalina Nuclear Power Plant.

Elektron-E16V circuit breakers made by KONTAKTOR plant in Dimitrovgrad (Russia) are used as input switches. Circuit breakers in input switches were dismantled, i.e. they operate as remotely controlled contactors. To ensure fire protection of busbars and feeder cable outputs, Zilberman sensor protection, which uses load current phase angle and responds only to the active component of the short-circuit current (KZ), was installed outside of the section. The control of normal and backup inputs of 0.4 kV sections is performed from the control panel, by using a remote control key. Remote switch position indication and fault warning alarm systems are also connected to the control panel. The main protection of 0.4 kV power transformer sections and busbars is installed on the high-voltage side, by using RT-40 and RP-23 type digital relays, which activate disconnection of LF2 Schneider Electric switches on the 6 kV side and Elektron Э16 on the 0.4 kV side.

Normal and backup inputs of Elektron E16V circuit breakers in auxiliary 0.4 kV switchgear in the 2-nd Power Unit and Room No 119 along with the relay protection set of auxiliary power transformers on the high voltage side had to be replaced at Ignalina Nuclear Power Plant.

The main objectives of the project were as follows: replacement of morally and physically obsolete equipment and improvement of power supply reliability for the auxiliary consumers of Ignalina Nuclear Power Plant.

AS PART OF THIS PROJECT, THE FOLLOWING WORKS WERE CARRIED OUT:

• Design, manufacturing, testing, and delivery of a new certified Siemens unit, intended to replace the following equipment in planned steps: 66 normal and backup inputs of Elektron E16V circuit breakers in auxiliary 0.4 kV switchgear sections and in Room No 119 of INPP along with the relay protection set of auxiliary power transformers on the high voltage side.
• A technical design for the replacement of the circuit breakers was prepared, including drawings, specifications, and the relevant documentation.
• Equipment transfer/acceptance tests were carried out at the manufacturer’s facility, including preparation of the procedures and program for the performance of equipment compliance testing at the manufacturer's facility.

UNIQUE CHARACTERISTICS OF THIS PROJECT:

1. Analysis of possible events in the auxiliary 0.4 kV system, intended for optimal selection of automatic circuit breakers and sensor protection.
2. Designing pilot samples of withdrawable carriages complete with various switches, including tests to determine their conformity with the technical requirements of INPP.
3. Manufacturing and testing of pilot samples in an independent laboratory, including testing of dynamic and thermal resistance as well as operating tests under emergency conditions, which can be significantly different from normal operating conditions.

The technical design for the replacement of equipment was prepared by our subcontractors ООО SPKB PROELEKTRO (specialized design centre PROELEKTRO, a limited liability company, Kiev, Ukraine).

Specified tests of the equipment were carried out at the facilities of the Electrotechnical Institute (Warsaw, Poland).