Early warning method, device and storage medium based on insulation flashover rate under overvoltage

Abstract

The invention discloses an early warning method based on the insulation flashover rate under overvoltage, which includes: according to Thevenin's theorem, the southern power grid system is equivalent to the corresponding bus bar of each substation in the predetermined network to obtain the equivalent power supply; Ground wire parameters, tower model and line transposition, establish a transmission line simulation model, and form a complete electromagnetic transient simulation model including power supply, transmission line, power plant generator and circuit breaker; based on the complete electromagnetic transient simulation model, calculate separately Obtain the overvoltage distribution on the target transmission line when the circuit breaker is closed and single-phase reclosing, and further calculate the total flashover rate of the three-phase full line under the two working conditions; when the total flashover rate of the three-phase full line under the two working conditions When the network rates are all lower than the preset threshold, the first warning information is generated. The embodiment of the present invention can guide the operation overvoltage protection more reasonably, so as to reduce unnecessary addition of closing resistors, avoid reduction of switch reliability, and reduce investment.

Description

technical field [0001] The invention relates to the field of electric power technology, in particular to an early warning method, device and storage medium based on the insulation flashover rate under overvoltage. Background technique [0002] In order to ensure the safe operation of new projects, the national standard stipulates that "the relative ground statistical overvoltage generated by closing and single-phase reclosing on the line should not be greater than 2.0p.u." For safe operation, it is generally recommended to install closing Resistance, but it is unreasonable to use it as the criterion of whether to install closing resistance. The reasons are as follows: (1) The actual insulation level of the line and the distribution of the probability of line overvoltage along the line are not considered; (2) The switch operating mechanism with a closing resistor is complicated, and the installation of unnecessary closing resistors reduces the reliability of the switch And i...

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Problems solved by technology

[0002] In order to ensure the safe operation of new projects, the national standard stipulates that "the relative ground statistical overvoltage generated by closing and single-phase reclosing on the line should not be greater than 2.0p.u." For safe operation, it is generally recommended to install closing resistance, but it is unreasonable to use it as the criterion of whether to install closing resistance

The reasons are as follows: (1) The actual insulation level of the line and the distribution of the probability of line overvoltage along the line are not considered; (2) The switch operating mechanism with a closing resistor is complicated, and the installation of unnecessary closing resistors reduces the reliability of the switch And increased investment; (3) The regulation of "should not be greater than 2.0p.u." is difficult to quantify. For the sake of safety, some units will install closing resistors for all calculated phase-to-ground statistical overvoltages greater than 2.0p.u. Lines greater than 2.0p.u. can cancel the closing resistance of the circuit breaker but cannot be canceled; (4) The insulation of the line is self-restoring insulation, 5.3 of GB311.2-2013 "Guidelines for Insulation Coordination of High-Voltage Power Transmission and Transformation Equipment" It is stipulated that "the statistical method should be used for the self-restoring insulation of the line. When using the statistical method, it is first necessary to determine the acceptable failure rate based on technical and economic analysis and operating experience." Therefore, the safe operation of the line should ultimately be reflected in the failure rate of the line. , Article 5.2 of GB311.2-2013 stipulates that "the range of acceptable failure rate caused by operating overvoltage is (0.01~0.001) times / per operation"

Therefore, it is unreasonable to install the closing resistor directly when the overvoltage exceeds the allowable range of the standard in the prior art

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