Method of Measuring Transformer Protection Vector by Controlling Two-way Current Phase and Amplitude

Abstract

The invention discloses a method for measuring a transformer protection vector by controlling the phase and the amplitude of two paths of current. The method comprises the steps that current is simultaneously piped into to the primary side of the CT of the two sides of a transformer under the condition of disconnection of the circuit breakers and the isolation switches of the two sides of the transformer; the size and the phase of the two paths are adjusted so that the size and the phase are enabled to be consistent with the actual load current ratio and the phase of the two connecting sides of the transformers; and A-phase, B-phase and C-phase current is added to the two sides, the current phase of differential protection of the transformer is detected to be consistent with the phase of the added primary current and differential current is zero. According to the method for measuring the transformer protection vector by controlling the phase and the amplitude of two paths of current, current is added to the two sides of the transformer so that the test equipment is enabled to be small in capacity, low in weight, easy to operate, less in investment and high in efficiency, and determination of the phase of the transformer protection device can be completed before production. Temporary protection is not additionally required in power transmission of the line so that operation can be reduced without changing the operation mode, manpower and material resource input can be reduced and safe operation of the power grid can be enhanced.

Description

technical field [0001] The invention relates to the technical field of electric power systems, in particular to a method for measuring transformer protection vectors by controlling two current phases and amplitudes. Background technique [0002] The power industry standard "Inspection Regulations for Relay Protection and Power Grid Safety Automatic Devices" clearly requires: "8.2.2. For devices that are newly installed or have a large change in the equipment circuit, they must be tested with primary current and working voltage before they are put into operation. inspection and judgment." [0003] The content of the inspection mainly includes: measuring the amplitude and phase relationship of voltage and current, measuring the differential current of differential protection, checking the unbalanced output of the phase sequence filter, etc. [0004] However, in the process of actual project commissioning, in order to determine the side phase of the protection device, it is ne...

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Problems solved by technology

[0004] However, in the process of actual project commissioning, in order to determine the side phase of the protection device, it is necessary to consider the arrangement of various power grid operation modes, the power transmission components must have a certain load, and temporary protection and circuit breakers need to be added in series. Therefore, when there are many equipment in production, the power grid The arrangement of the operation mode is complicated, and there are many equipment operations at one time. It is necessary to install temporary protection and calculate the fixed value of temporary protection. The workload of secondary protection and safety automatic device phase measurement is heavy, which affects the efficiency and safety of production.

[0005] The current relay protection tester is only used for the functional test of the relay protection device itself. It is a test tool for secondary operations. The output voltage is low, the current is small, and the capacity is limited. It can only be used in PT (potential transformer voltage transformer) and The CT (Current Transformer Current Transformer) secondary circuit adds voltage and current, and does not have the ability to apply voltage and current to the primary side of PT and CT. Therefore, it cannot detect the correctness of the wiring between the primary and secondary circuits of PT and CT. Moreover, the secondary side equipment is generally charged, so temporary protection needs to be installed, which poses a great danger to the operator, and the workload of setting calculation is large

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