A protection method for an inverter station of a HVDC power transmission system

Abstract

The invention discloses a method for protecting an inverter station of a high-voltage direct current transmission system, which includes the following steps: Step 1: Obtain the three-phase voltage signal at the commutation bus of the inverter station and the three-phase current signal at the head end of the AC line; and calculate the voltage signals respectively Fault component and current signal fault component; Step 2: Judging whether there is a fault, and confirming that the fault is inside or outside the inverter station; Step 3: If it is outside the inverter station, judge whether there is a fault protected by the inverter station The setting value is satisfied, if not, return to step 1; if yes, block the protection of the inverter station whose setting value is satisfied t x Time, the fault is removed by the AC line protection action outside the inverter station area; Step 4: If it is a fault in the inverter station area, judge whether there is an inverter station protection setting value that is satisfied, if not, return to step 1; If there is, no change will be made; the invention can prevent the inverter station protection from misoperation under the fault of the AC line outside the area, and does not affect the quickness and sensitivity of the inverter station protection.

Description

technical field [0001] The invention relates to the technical field of power system protection, in particular to a method for protecting an inverter station of a high-voltage direct current transmission system. Background technique [0002] The high-voltage direct current transmission system has large transmission capacity, long transmission distance and low transmission loss, so it occupies an increasingly important position in my country's power structure. The basic principle of high-voltage direct current transmission is: the rectification station is used to rectify the three-phase alternating current at the transmission end of the high-voltage direct current transmission system, and the three-phase alternating current is converted into direct current. The substation performs inversion to convert DC power into three-phase AC power, and the electric energy is transmitted to the grid or power station connected to it through multiple AC lines outside the inverter station are...

AI Technical Summary

Problems solved by technology

However, increasing the setting time of the inverter station protection reduces the quickness of the inverter station protection to the faults in the area and prolongs the impact time of the faults in the area on the inverter station equipment, so increasing the setting time of the inverter station protection will increase The risk of damage to inverter station equipment under large inverter station faults; increasing the setting value of inverter station protection will reduce the sensitivity of inverter station protection and increase the risk of refusal action of inverter station protection under internal faults

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