Power transmission line parameter online measurement method based on fault wave recording

Abstract

The invention relates to a power transmission line parameter online measurement method based on fault wave recording, which is characterized by comprising the steps: GPS clocks of wave recording devices are utilized for carrying out integral hour startup to obtain positive sequence voltage and current at two ends of a line and the voltage and the current are saved in the wave recording devices at two ends in the form of wave recording files respectively; when the double-circuit line with mutual inductance has an earth fault outside a region, the zero sequence current generated by the fault is utilized for simultaneously starting the wave recording devices at two ends of the line, the synchronous sampling of the zero sequence voltage and the current at two ends of the line in the region is carried out, and a zero sequence sensitive II segment startup element is further equipped; and a central dispatching computer reads the positive sequence voltage and the current values at the two ends and measures the positive sequence parameters of the line. The zero sequence voltage and the current values at two ends are read, thereby measuring the zero sequence parameters of the line. The method does not need to cut off the power, the operation is convenient, and the wave recording devices can be used for the power transmisison line parameter online measurment, thereby making up for the defects of non-synchronous problem when measuring the positive sequence parameters and no zero sequence power supply when measuring the zero sequence parameters by using the prior online measurment device, and improving the line parameter measurment times and the measurement precision.

Description

technical field [0001] The invention relates to the measurement of transmission line parameters, in particular to an online measurement method for transmission line parameters based on fault wave recording. Background technique [0002] National electric power industry standard DL / T559-94: "220KV ~ 500KV Power Grid Relay Protection Operation Regulations" requires relay protection setting: the zero-sequence impedance of overhead lines and cables, and other parameters that have a greater impact on relay protection should be measured value. However, the existing line parameter measurement method is blackout measurement. The measured line must be powered off and disconnected from the power grid. The positive sequence and zero sequence parameters of the line are measured through different measurement tests. Generally, after the test power is applied to the line, the various states of the line are measured by meters such as voltmeter, ammeter, power meter, and frequency meter, an...

AI Technical Summary

Problems solved by technology

However, the existing line parameter measurement method is blackout measurement. The measured line must be powered off and disconnected from the power grid. The positive sequence and zero sequence parameters of the line are measured through different measurement tests.

Generally, after the test power is applied to the line, the various states of the line are measured by meters such as voltmeter, ammeter, power meter, and frequency meter, and the corresponding line parameter values ​​are calculated by using the corresponding formula after reading the table value manually. Although it is more accurate than the parameter values ​​calculated purely through theory, the power failure measurement affects the normal load power supply and the optimal distribution of the power flow, and there are also disadvantages such as heavy measurement equipment, cumbersome operation, time-consuming and labor-intensive, especially the disconnection of the line before and after the measurement , Grounding, closing and many operations in the measurement process have potential safety hazards for personnel and equipment. In the measurement, the two ends of the line and the dispatching are generally connected by radio, which has poor reliability and is easy to cause coordination errors.

In addition, the existing wave recording device can record waveforms under fault conditions, but there is no related application for line parameter measurement, and the timing start based on the GPS hourly clock cannot be set during normal operation, and it cannot be used for normal operation. Synchronous online measurement of the positive sequence parameters of the transmission line; in the case of an external ground fault, parameters such as zero sequence impedance cannot be measured

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