PL150430B1 - System for additionally protecting against indesirable effects of short circuits a medium voltage ht/mt transformer power substation - Google Patents

Description

PATENT DESCRIPTION 150 430

REPUBLIC

POLAND

reading room

Additional patent to patent No.- Pending: θ ^{5 11 11}

Priority ____

Int. Cl. ⁵ H02H 7/26

Lfc <Patent / P. 256225 /

OFFICE

PATENT

RP

Application announced: 87 06 15

Patent description published: 1990 10 31

Inventor: Zbigniew Kluska

The holder of a patent: Main Office of Mining Studies and Projects Biuro Projektów Górniczych, Katowice / Poland /

SYSTEM OF ADDITIONAL PROTECTION OF MEDIUM VOLTAGE POWER SWITCHGEAR, POWERED FROM A HV / MV TRANSFORMER AGAINST SHORT-FAILURES

The subject of the invention is a system of additional protection of a medium voltage power switchgear supplied from an HV / MV transformer against the effects of short-circuits, especially in power stations for hard coal mines. In the currently known state of the art, in power station systems, medium voltage switchgears supplied from HV / MV transformers with with auxiliary DC voltage, I do not have protection in the event of a voltage loss caused by, for example, the wear of the battery or, more often, a break in the auxiliary DC voltage circuit. in the power source or on the transmission route · No safeguards will prevent the loss of auxiliary voltage necessary to activate the shutdown coil MV circuit breaker after activation of the protections · which may become the cause of a dangerous failure at the moment of occurrence short circuit suppression

The aim of the invention is to achieve an additional protection system for the MV power switchgear supplied from the HV / MV transformer against the effects of short-circuits in the event of a complete loss of the auxiliary voltage of the DC speed, which in an uncomplicated and reliable manner will eliminate the current lack of such a lack of such a system using additional elements compatible with the existing overcurrent protection circuits in the switchgear ·

The specified goal has been achieved, and the technical task set has been solved in the system according to the invention in such a way that the existing secondary circuits of the high-speed transformers include the increasing-speed releases built into the MV circuit breaker and the auxiliary relays and high-speed elements of the overcurrent relay, whose instantaneous NC contacts are turned on with a time relay between the poles of the auxiliary voltage of the constant speed of the switchgear, while the closed short contact of the time relay is included in the auxiliary relays circuit, ensuring the closing of the switching circuit MV circuit breaker after activation of protections

150 430

150 430 against short-circuits The advantage of the system according to the invention is that there is no need to supply auxiliary voltage to the MV circuit breaker releases, because MV tripping / opening / breaking occurs with the use of short-circuit speed energy, which guarantees the effectiveness of

The subject of the invention is explained in more detail in the attached drawing, which is a schematic diagram of the protection system in non-energized state. The thicker tension line and the axis are those elements that should be added to the known and used protection system in the MV switchgear bay. The high-speed circuit of the transformers Tli and T13 is overcurrent protection, consisting of an overcurrent relay element K33 and K42, acting to trip in the MV switchboard of the Q circuit breaker by means of the Q / CW2 / and Q / CW3 incremental releases. Timer, instantaneous and delayed contacts of the K33 relay and the K53 time relay coil supplied with the auxiliary DC speed voltage of the MV switchgear

In the case of a loss of the auxiliary voltage of the DC speed and a short circuit, the overcurrent element of the K33 relay is activated and its instantaneous break contacts are activated, causing the K53 time relay to de-energize. time contact of the K53 time relay is the time delay contact and their activation occurs, which will open the Q circuit breaker in the MV switchgear and switch off the short-circuit

Claims (1)

Patent claim The system of additional protection of medium voltage power switchgear, supplied from the HV / MV transformer against the effects of short-circuits in the event of complete loss of the auxiliary voltage of direct speed, characterized by the fact that the secondary circuits of the high-speed transformers / Tli and T13 / the triggers are incrementally switched on / Q / CW2 / and / Q / CW3 / switch / 0 / and auxiliary relays / K41 and K42 / and speed units of the overcurrent relay / K33 / whose instantaneous NC contacts are connected in series with the time relay / K53 / between the poles of the auxiliary voltage of the constant speed switchgear, while the time-delay short contact of the time relay / K53 / is on, in the auxiliary relays circuit / K41 and K42 / Ł-C Department of Publishing of the UP RP. Circulation 100 copies Price 1500 PLN!