A test method for the DC shunt coefficient of the grounding grid of the converter station

Abstract

The invention discloses a method for testing a direct current shunting coefficient of a grounding grid of a convertor station. The method comprises the following steps: 1) acquiring a rated current parameter of the convertor station, and selecting a current meter; 2) acquiring the total number N of grounding down conductors of inlet-outlet line portal frames at all voltage levels of the convertor station; 3) operating the convertor station by a mode for taking an instation grounding grid as a grounding electrode, and measuring the unbalanced earth current Idsg of the system during stable-state operation under the mode by adopting the current meter selected in the step 1); 4) measuring the current of the grounding down conductors of all the portable frames by the direction which is the same as the forward direction of the current defined in the step 3), defining measurement values from I1 to IN of all the down conductors, and determining a sum Iout of the flow-out current, wherein the Iout conforms to the formula (shown in the Specification), and i in the formula is equal to the number from 1 to N; 5) determining an earth shunting coefficient SF of the grounding grid of the convertor station, wherein the SF conforms to the formula (shown in the Specification). According to the method, transportation and mounting of high-capacity power supplies can be avoided; the interference of a power frequency signal is avoided; furthermore, the difficulty that a phase difference needs to be calculated when a power frequency or pilot frequency current is injected is solved.

Description

technical field [0001] The invention relates to a method for testing the shunt coefficient of a grounding grid, in particular to a method for testing a DC shunt coefficient of a converter station, which is suitable for measuring the shunt coefficient of a converter station using the grounding grid in the station as a temporary special operation mode of the ground electrode, and belongs to the electric power industry. System grounding grid characteristic parameter measurement field. Background technique [0002] In addition to providing working grounding for all equipment in the converter station, the grounding network of the converter station also provides a fast discharge channel for the current when the converter station is struck by lightning, the system is short-circuited, and the arrester protection action is activated. At the same time, the voltage equalizing belt of the grounding grid also plays the role of voltage equalizing, improving the contact voltage and step vo...

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Problems solved by technology

Because the former method is put into operation, it is almost impossible to cut off the power of all lines at the same time, and it is very difficult to implement; the second method is because the grounding grid, the overhead lightning conductor, and the cable shielding layer jointly constitute a resistance and inductance network, and the injected The current is either a 50HZ power frequency current or a 45HZ-55HZ different frequency current. When testing, the influence of the shunt is either ignored, or due to the limitation of the equipment, the modulus value is directly added. These test methods have certain errors.

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