Double circuit line non-identical phase-over-line grounding reactance distance protection method
A double-circuit line, grounding reactance technology, applied in emergency protection circuit devices, electrical components, etc., can solve problems such as threats to the stability of the power system, steady-state overrun, and loss of safe operation of the power system.
Active Publication Date: 2016-08-24
STATE GRID PUTIAN ELECTRIC POWER SUPPLY +2
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Problems solved by technology
The additional impedance generated by the transition resistance is resistive-inductive or resistive-capacitive, which may easily cause the grounding impedance distance protection to refuse to operate or the steady state to exceed
Misoperation or refusal of relay protection will bring significant losses to the safe operation of the power system, and may even threaten the stability of the power system
Method used
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[0016] Please check figure 1 , figure 1 Among them, PT is the voltage transformer 2, and CT is the current transformer 3. The protection device 1 samples the voltage waveform obtained by the voltage transformer 2 and the current waveform obtained by the current transformer 3 respectively at the place where the transmission line protection is installed to obtain instantaneous values of voltage and current.
[0017] The protection device 1 uses the Fourier algorithm to calculate the instantaneous value of the voltage and current obtained by sampling, and calculates the fault phase voltage at the installation place of the I-circuit line protection of the parallel double-circuit line on the same pole fault phase current and zero sequence current Among them, φ=phase A of the I-circuit line, phase B of the I-circuit line, and phase C of the I-circuit line.
[0018] Furthermore, the protection device 1 calculates the zero-sequence current phase angle α=r of the II circuit li...
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The invention discloses a double-circuit line non-same-name-phase overline grounded reactance distance protection method. The method includes the steps that firstly, the fault phase voltage, the fault phase current and the zero-sequence current of a protecting and installing position of a circuit line I of a double-circuit line are measured; the zero-sequence current of a circuit line II of the double-circuit line is calculated, and the voltage phase angle of a grounded fault point of the circuit line I is estimated by using the phase angle of the sum of the zero-sequence current of the circuit line I and the zero-sequence current of the circuit line II; whether the conclusion that the phase angle of the voltage, ahead of the voltage of the grounded fault point of the circuit line I , in the protecting and setting range of the circuit line I is within the range from minus 165 degrees to 15 degrees is established or not, and if yes, a protecting device sends an actuation signal for tripping. Only single-end single-circuit line electric amount is used, motion performance is not affected by operation modes of an electric power system, the influence on motion performance of an on-the same-tower double-circuit line non-same-name-phase overline grounded reactance distance relay by zero-sequence mutual inductance between the lines, transition resistance and a load current is eliminated, and the protecting range is stable and reliable.
Description
technical field [0001] The invention relates to the technical field of power system relay protection, in particular to a distance protection method for non-identical phase-cross-line grounding reactance of a double-circuit line. Background technique [0002] The double-circuit line paralleled on the same pole has a small footprint, low cost, and stable and reliable operation when connected to the grid. It has become a common transmission line connection method in the power system. There is zero-sequence mutual inductance between double-circuit lines on the same pole, and the zero-sequence mutual inductance affects the zero-sequence compensation coefficient, thereby generating additional impedance. The additional impedance caused by the zero-sequence mutual inductance will cause the fault impedance measured by the protection device to be greater than the actual fault When a ground fault occurs near the protection setting range in the double-circuit line protection area of t...
Claims
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IPC IPC(8): H02H7/22
Inventor 林富洪陈文景徐致远李振华林明星
Owner STATE GRID PUTIAN ELECTRIC POWER SUPPLY