A test device for DC bias performance of voltage transformer

Abstract

The invention discloses a direct-current bias magnetic performance test device for a voltage mutual inductor. The test device comprises a first voltage regulator, a second voltage regulator, a high-flux-leakage transformer, a boost full-wave rectifier circuit and a filter capacitor. Alternating-current voltage is input into the input end of the first voltage regulator, and the output end of the first voltage regulator is connected with a primary winding of the high-flux-leakage transformer; alternating-current voltage is input into the input end of the second voltage regulator, and the output end of the second voltage regulator is connected with the input end of the boost full-wave rectifier circuit; the filter capacitor is connected between the output end of the boost full-wave rectifier circuit and a grounding end; the output end of the boost full-wave rectifier circuit is connected with the reference end of a secondary winding of the high-flux-leakage transformer; the voltage output end of the secondary winding of the high-flux-leakage transformer is connected with the test voltage output end of the test device. Accordingly, combined voltage is applied to the voltage mutual inductor through a simulation contact network, and a direct-current voltage component and an alternating-current voltage component are superimposed, so that direct-current bias magnetic performance of the voltage mutual inductor is tested.

Description

technical field [0001] The invention relates to the field of electric power technology, in particular to a test device for the DC bias magnetic performance of a voltage transformer. Background technique [0002] Electric traction is a form of rail transportation traction power that uses electric energy as power. It uses the power system or power plant as the power source, receives power from the power system through the traction substation, and supplies power to the electric locomotive and EMU through the catenary through step-down, frequency conversion or AC. [0003] The voltage transformer installed on the top of the electric traction locomotive is used to measure the catenary voltage and provide signal control power supply, and its nominal working voltage is 25kV. [0004] Existing high-speed railway locomotives use 50Hz AC-DC-VF AC drive mode. This driving method will generate a DC component on the catenary at the same time of rectification and inversion, so that the ...

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Problems solved by technology

At the same time, the iron core of the voltage transformer working under DC bias is easy to enter the saturated excitation state, which increases the AC excitation current.

The effective value of the composite current formed by the superposition of the DC excitation current and the AC excitation circuit often exceeds the continuous thermal current that the primary winding can withstand, causing the primary winding of the voltage transformer to overheat, exceeding the allowable temperature rise of the primary winding insulation, and finally causing interlayer Breakdown, voltage transformer damage

[0006] In the European standard BS EN50152-3-3:2001 "Installed equipment for railways - Particular requirements for AC switchgear - Part 3-3: Measurement, control and protection equipment used in special conditions of AC drive systems - Electromagnetic In "Single-phase Voltage Transformer", the requirements for the voltage transformer to operate under the condition that the DC bias voltage does not exceed 4kV are put forward, but the standard does not require actual tests, so the technical conditions for the test methods and test devices are not proposed.

[0007] National Standard GB 1207-2006 "Electromagnetic Voltage Transformer", National Standard GB / T 16927.1-2011 "General Test Requirements for High Voltage Test Technology Part 1", Railway Standard TB / T 3038-2002 "Electrified Railway 50kV, 25kV Voltage In "Transformers", there is no mention of the DC bias test of the voltage transformer

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