Three-phase voltage phase sequence memory and alarm device

Abstract

The invention discloses a three-phase voltage phase sequence memory and alarm device, which comprises a differentiating circuit, a first voltage comparator, a second voltage comparator, a third voltage comparator, a fourth voltage comparator, a fifth voltage comparator, a 50VDC, a working power supply, a phase sequence relay, a five-input AND gate circuit and an alarm. The input end of the differentiating circuit is connected with UA, the output end is connected to the positive electrode of the fifth voltage comparator, and the negative electrode of the fifth voltage comparator is grounded, the input end of the first voltage comparator is connected with the UA and UC respectively, the input end of the second voltage comparator is connected with UB and the UA respectively, and the input endof the third voltage comparator is connected with the UA and the ground; the input end of the fourth voltage comparator is respectively connected with the UA and the 50VDC. According to the invention, the plurality of comparators and the differentiating circuit are arranged, and the voltage output capable of representing the three-phase voltage phase sequence is obtained according to the level principle of the phase sequence change, so that the three-phase voltage phase sequence memory and change alarm can be realized, the circuit is simple, and the performance is reliable.

Description

technical field [0001] The invention relates to the technical field of three-phase voltage phase sequence memory, in particular to a three-phase voltage phase sequence memory and alarm device. Background technique [0002] At present, isolating switches, transformers, etc. are common primary equipment in substations, and electric mechanisms are generally used for opening and closing or gear adjustment operations. The motor is powered by three-phase voltage, and the forward or reverse rotation of the motor is realized by adjusting the phase sequence of the three-phase voltage, so that the opening and closing of the disconnector and the lifting and lowering of the main transformer gear are realized through the connecting rod. [0003] The three-phase power supply of the isolating switch is taken from the AC power panel cabinet in the main control room or protection room of the substation, and the service life of the primary equipment such as the AC and DC system for the substa...

AI Technical Summary

Problems solved by technology

When the substation AC / DC system is transformed or other situations are encountered, the phase sequence of the three-phase voltage may change, which will cause the isolation switch of the substation to be inoperable, or even damage the operating mechanism

There is no three-phase voltage phase sequence memory and alarm device in the prior art, which can determine the correct phase sequence and memorize it in the debugging stage before the isolator is put into operation. When the phase sequence of the power supply changes after it is put into operation, it cannot be detected and reported in time. Call the police

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