On site precision detecting test line for high-voltage current transformer

Abstract

The invention relates to a high-voltage power transmission and transformation current detecting technology which discloses an on-site accuracy detecting and testing line of a high-voltage current mutual inductor and is adapted to the on-site accuracy detection of an ultra-high voltage (750 kV) current mutual inductor. The on-site accuracy detecting and testing line of the high-voltage current mutual inductor comprises a voltage regulator, a current raising device, a compensated capacitor, a main loop, a testing power supply which is electrically connected with the first side of the voltage regulator, a standard current mutual inductor, an on-site current mutual inductor and a mutual inductor check meter, wherein the standard current mutual inductor and the on-site current mutual inductor are arranged on the main loop, the mutual inductor check meter is electrically connected with the standard current mutual inductor and the on-site current mutual inductor, the second side of the voltage regulator is electrically connected with the first side of the current raising device, and the second side of the current raising device is electrically connected with the main loop. The invention is characterized in that the compensated capacitor is connected in the main loop in series.

Description

technical field [0001] The invention relates to a current detection technology for high-voltage power transmission and transformation, in particular to a test circuit for on-site accuracy detection of a high-voltage current transformer, which is suitable for on-site accuracy detection of an ultra-high voltage (750kV) current transformer. Background technique [0002] The current transformer is the main component of the electric energy metering device in the substation, and its accuracy is very important for the electricity metering. In the previous on-site inspection of transformers in the power system, it was found that some gateway meters had large deviations. For example, in 2000, the comprehensive error of 500kV outgoing line measurement in a power plant exceeded 5%, and the on-site inspection of a 330kV substation found that all capacitive voltage transformers exceeded Poor, these problems will have a great impact on system measurement. For the power transmission and t...

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Problems solved by technology

The parallel compensation capacitor is connected to the primary side of the voltage regulator, and its capacitive reactance compensates the main circuit after changing the ratio of the voltage regulator. Since the voltage regulator is actually a step-down transformer, its ratio is less than 1, so the capacitive reactance changes to two After the secondary side, the actual compensation capability decreases; on the other hand, since the compensation capacitor is connected to the primary side of the voltage regulator, the reactive current of the compensation capacitor still needs to pass through the voltage regulator, so that the voltage regulator needs to provide active power for the main circuit. The (resistive) component needs to pass reactive power compensation current, so the capacity required for the voltage regulator is very large, which is quite unfavorable for the cost of configuring the voltage regulator and the difficulty of manufacturing technology.

[0007] In addition, using the above-mentioned existing technology, it is also reflected from the field measurement process that because the secondary load of the voltage regulator is very large, the primary voltage may have a large drop during the test process. During the field test, the primary side voltage of the voltage regulator was about 400V at the beginning. When the current flow reached about 2000A, the primary side voltage had dropped to about 310V. It was difficult for the capacitor to guarantee its compensation capability, resulting in the failure of the final test.

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