Negative sequence element accurate test method in re-pressing locking

Abstract

The present invention provides a negative sequence element accurate test method in re-pressing locking. A compound voltage lock comprises a low-voltage lock, a composite sequence voltage lock and a zero-sequence voltage lock. When the voltage of a bus is lower than a low-voltage fixed value of the low voltage lock, the zero-sequence voltage is higher than the zero-sequence voltage fixed value of the zero-sequence voltage lock or the negative sequence voltage is higher than the negative sequence voltage fixed value of the composite sequence voltage lock, the composite voltage elements are moved, and when two-phase short-circuit fault is generated, a non-fault-phase bus voltage is unchanged; the voltage amplitudes of the two buses with the fault phases are reduced, the angle is changed, theincluded angle between the two voltages is reduced, the two voltages maintain the symmetrical relation, if an A phase is a non-fault phase, when a B phase and a C phase generate short circuit, the non-fault bus voltage Ue=U1+U2=57.7V, the UM is taken as a bus voltage when the condition is normal, the UK is a bus voltage when there is a fault, a is the deflection angle of the voltage, and [Alpha] is a unit vector operator which is not less than 120 degrees; and the fault phase voltage and the deflection angle is as shown in the description. Therefore, it is avoided that the zero-sequence voltage reaches a fixed value to cause composite voltage element motion.

Description

technical field [0001] The invention relates to an accurate testing method for negative sequence components in complex voltage lockout, in particular to a precise test method for negative sequence components in complex voltage lockout for preventing protection of busbars with a voltage level of 220kV and below. Background technique [0002] In the power system, the busbar protection with voltage level of 220kV and below introduces the composite voltage blocking realized by the busbar voltage in order to prevent the components on the busbar from being cut off due to accidental protection. Compound voltage blocking is usually composed of low voltage blocking, complex sequence voltage blocking and zero sequence voltage blocking. When the phase voltage of the bus is lower than the low voltage setting value, the zero sequence voltage is higher than the When the voltage is fixed, the composite voltage element operates, and the protection will output. The relationship between the t...

AI Technical Summary

Problems solved by technology

When carrying out the negative sequence voltage fixed value inspection, the debugger often uses the bus voltage to test when the bus is single-phase grounded. Since the zero sequence voltage is also generated when the single phase is grounded, when the zero sequence voltage reaches the zero sequence voltage fixed Make the composite voltage element act, which causes inconvenience to the debugging of relay protection

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