In recent years, 110kV and below the transformer, the application of on-load tap-changer tap more and more, mostly domestic. Most of the tap-changer adopts resistive combination type. The overall structure can be divided into three parts: control part, transmission part and switch part. The on-load tap-changer plays an important role in improving the voltage pass rate of the power supply system. At present, relying on the power supply of the county power grid voltage regulator means, mainly by the on-load voltage regulator to achieve. Which put the on-load tap-changer and tap-changer operation and maintenance work pushed to an important position. Keywords: transformer switch operation and maintenance manual voltage regulation

 

In recent years, 110kV and below the transformer, the application of on-load tap-changer tap more and more, mostly domestic. Most of the tap-changer adopts resistive combination type. The overall structure can be divided into three parts: control part, transmission part and switch part. The on-load tap-changer plays an important role in improving the voltage pass rate of the power supply system. At present, relying on the power supply of the county power grid voltage regulator means, mainly by the on-load voltage regulator to achieve. Which put the on-load tap-changer and tap-changer operation and maintenance work pushed to an important position.

 

Maintain content and requirements

 

(1).The on-load tap-changer put into operation before the oil pillow should be checked, the oil level should be normal, should be no leakage of oil, control box to moisture good. Manual operation of a cycle (that is, lifting a cycle), gear indicator and counter should be correct action, the limit position of the latch should be reliable, manual and electric control interlock should be reliable.

 

(2). The on-load tap-changer gas protection, heavy gas into the trip, light gas signal. This is the same as the gas protection requirements of the transformer body. We usually say that the body of the gas relay for the "large gas", said the on-load tap-changer gas relay é? Small gas. "Gas relay should be installed in the operation to facilitate the safe deflation position. After the installation of the switch gas relay, the operator should be deflated when necessary (when the gas inside the cylinder) is in place.

 

(3). The on-load tap-changer of the electric control should be correct, reliable power supply, the terminals are in good contact. Drive the motor rotation is normal, turn right, the fuse rated current according to the motor rated current of 2 to 2.5 times the configuration.

 

(4). The power control circuit of the on-load tap-changer, the electric operation button installed on the control panel, and the on-load tap-changer on the control body of the transformer should be in good condition, the power indicator and the gear The indicator should be intact and the extreme position of the electrical latch should be reliable.

 

(5). The on-load tap-changer electric control circuit should be set up current blocking device, the setting value of the main transformer rated current of 1.2 times the current relay return coefficient greater than or equal to 0.9. When using automatic voltage regulator, the main transformer control screen must have action counter, automatic voltage regulator voltage transformer secondary disconnection should be correct and reliable.

 

(6). The new or overhaul after the on-load tap-changer, should be in the transformer no-load operation, in the main control room with remote electric operation button and the transformer in the field of manual equipment, try to operate a cycle, gear and voltage The correct indication of the electrical position at the limit position is reliable and can be transferred to the dispatching position required for dispatching with load operation and enhanced monitoring.

 

(7). The attendant according to the dispatch of the voltage curve and voltage signal, automatic voltage regulator operation. Each operation should carefully check the tap action voltage current changes (each time a file for a time), and make a record.

 

(8). Two on-load tap-changer parallel operation, allowing the transformer 85% rated load current under the tap change operation. But can not be in a single transformer on the two consecutive tap operation. It is necessary to perform a tap change operation of another transformer after a tap change operation of a transformer is completed. An on-load tap-changer and an unloaded voltage regulator transformer must be connected to the on-load tap-changer tap changer to the same or similar gear as the no-load tap-changer, even if two The primary voltage of the main transformer is the same or similar. It is strictly forbidden to adjust the on-load tap-changer when the on-load tap-changer and the no-load voltage regulator are operated side by side.

 

(9). Duty personnel on-load tap-changer control, should be carried out according to inspection requirements, before and after operation should pay attention to and observe the presence or absence of gas in the gas relay.

 

(10). The operation of the on-load tap-changer gas relay signal or the on-load tap changer oil tank, the operation is prohibited and open the power isolation switch.

 

(11). In operation, on-load tap-changer gas relay heavy gas protection should be connected to trip. When the light gas frequent action, the duty officer should do a good job recording and report scheduling, stop the operation, analyze the reasons for timely processing.

 

(12). The on-load tap-changer oil quality supervision and inspection cycle:

 

①. every 6 months of operation should take oil samples for pressure test once, the oil pressure value should not be less than 30kV / 2.5mm. When the oil pressure between (25 ~ 30kV) / 2.5mm should be stopped between the use of automatic voltage regulator controller. If the oil pressure is lower than 25kV / 2.5mm, should stop the pressure operation and timely arrangements for oil change. When running 2 to 4 years or conversion operation up to 5000 when the oil change.

 

②. ontind tap changer body hanging core inspection.