Method for quickly diagnosing abnormal DC voltage measurement of converter station

Abstract

The invention discloses a method for quickly diagnosing abnormal DC voltage measurement of a converter station. The method comprises the following steps of S1: in a bipolar full-voltage operating modeof a DC system, collecting DC voltages UdH, UdM and UdN, DC current Id, high-end valve group inverter primary AC power Pacv1 and low-end valve group inverter primary AC power Pacv12, and calculatingthe pole DC power Pdc and the sum of two valve group inverter primary AC powers Pac of pole; S2: when the absolute value of UdN is greater than 0.5kV, determining that the UdN measurement is abnormal;when the absolute value of UdN is less than or equal to 0.5kV and the AC / DC power deviation, that is, the absolute value of Pdc-Pac is greater than 12MW, determining that the UdH measurement is abnormal; and when the absolute value of UdN is less than or equal to 0.5kV and the AC / DC power deviation, that is, the absolute value of Pdc-Pac is less than or equal to 12MW, determining that the UdM measurement is abnormal. The invention can detect abnormal faults in DC voltage measurement and determine specific fault measurement points in advance before an alarm is issued by the control and protection system, and can judge faults with abnormally large or small DC voltage measurements, effectively avoids the occurrence of forced DC shutdown events, and ensures the safe and stable operation of the DC transmission system.

Description

technical field [0001] The invention relates to a method for quickly diagnosing the abnormal DC voltage measurement of a converter station, which is suitable for the converter station of the Nanrui UHV technical route. Background technique [0002] As an important equipment of HVDC transmission system, the DC measurement system plays a vital role in the safe and stable operation of the DC system. During normal operation, the rectifier side controls the DC current, and the inverter station controls the DC voltage. The inverter station controls the actual DC voltage on the rectifier side near the reference value (rated value or step-down set value), and calculates the reference value of the DC voltage of the inverter station according to the current state of the DC system. The DC voltage measurement of the converter station mainly includes the DC line voltage measurement value U dH , Valve group connection bus voltage measurement value U dM , and the measured value of the n...

AI Technical Summary

Problems solved by technology

[0003] In recent years, DC voltage measurement abnormalities have occurred many times in the converter stations under the jurisdiction of China Southern Power Grid, which has affected the safe and stable operation of DC, and even caused forced shutdown of the DC system in severe cases.

Through debugging and simulation tests, it is found that the setting value of the current control and protection DC voltage monitoring function is too large, which can only reflect measurement faults and cannot reflect measurement abnormalities

When the DC control protection issues a DC voltage measurement abnormality alarm, the DC voltage has already experienced a relatively serious deviation

In addition, when the abnormal deviation of DC voltage measurement is small, the operating parameters such as DC power, voltage, and current do not change much, and it is difficult for operators to intuitively judge the abnormal measurement point and fault condition of DC voltage through the monitoring panel

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