AC-DC hybrid power grid pilot protection method and system based on voltage waveform comparison
A technology of AC/DC hybrid and voltage waveform, which is applied in the direction of automatic disconnection emergency protection devices, emergency protection circuit devices, electrical components, etc., can solve the problems of decreased fault sensitivity, insufficient, high sampling frequency requirements, etc., and achieve reliable judgment Faulty, good applicability, fast and good results
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Embodiment 1
[0049] figure 2 It is a schematic diagram of the AC / DC hybrid system model, where M and N are the busbars on both sides of the tie line of the AC / DC hybrid system, which is also the installation place of the relay protection device, and the M side is the inverter side, and this side is used as an example for illustration. u m and i m are the measured voltage and measured current of the relay protection device on this side, respectively, and point R is the reference point on the line.
[0050] combine figure 1 , when there is no fault, or there is a fault outside the protected area such as k1 or k2, that is, the line between MRs is intact, at this time through the u at the measurement point M m and i m , based on a certain mathematical model of the line, the voltage u at the reference point R can be calculated R . The calculation formula is as follows:
[0051]
[0052] Wherein, P is the parameter matrix of the line MR. Selecting different line models will correspond ...
Embodiment 2
[0107] This embodiment provides a longitudinal protection system for an AC / DC hybrid power grid based on voltage waveform comparison, including:
[0108] (1) a current and voltage acquisition module, which is used to obtain the corresponding measurement voltage and measurement current with any endpoint at both ends of the protected line as the measurement point;
[0109] (2) a reference voltage calculation module, which is used to calculate the voltage at the reference point as the reference voltage according to the known line parameter model; wherein, the reference point is located outside the protected line;
[0110] (3) a fault point judging module, which is used to determine whether the fault point is located between the measurement point and the reference point according to the waveform similarity between the measurement voltage and the reference voltage;
[0111] (4) Logic comparison module, which is used to judge whether the fault point is located inside the protected l...
Embodiment 3
[0114] This embodiment provides an AC / DC hybrid grid longitudinal protection system based on voltage waveform comparison, which includes two relay protection devices that communicate with each other, and the relay protection devices are respectively installed at both ends of the protected line; the A protective relay, configured to:
[0115] Take any endpoint at both ends of the protected line as the measurement point to obtain the corresponding measurement voltage and measurement current;
[0116] According to the known line parameter model, calculate the voltage at the reference point as the reference voltage; wherein, the reference point is located outside the protected line;
[0117] According to the waveform similarity between the measured voltage and the reference voltage, it is judged whether the fault point is between the measurement point and the reference point;
[0118] Use longitudinal comparison logic to judge whether the fault point is inside the protected line,...
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