Tault component transformer longitudinal error protecting method with maximum side zero sequence ratio brake
A fault component and zero-sequence current technology, applied to emergency protection circuit devices, electrical components, etc., can solve the problem that the zero-sequence current cannot be completely eliminated, and achieve the effect of avoiding inconsistent errors
Inactive Publication Date: 2008-02-06
ZHEJIANG UNIV
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[0005] The technical problem to be solved by the present invention is aimed at Y 0 The side three-phase current transformation method cannot completely eliminate the influence of zero-sequence current, and a transformer longitudinal differential protection method with maximum zero-sequence current fault component ratio braking is provided. component and the maximum value of the fault components of the zero-sequence current of each neutral point grounding side or branch of the transformer are weighted and summed to form the fault component of the brake current containing the zero-sequence current fault component. The fault component of the braking current and the fault component of the differential current of the corresponding phase constitute the criterion for the ratio braking of the fault component of this phase. When the fault component of the differential current is greater than the fault component of the braking current containing the zero sequence current fault component And when it is greater than the minimum operating current, output the action signal of the fault component ratio braking element of this phase
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[0017] A transformer longitudinal differential protection method with maximum zero-sequence current fault component ratio braking, which can be achieved through the circuit block diagram of a transformer longitudinal differential protection element with maximum zero-sequence current fault component ratio braking shown in Figure 3 to Figure 5 be achieved. The element consists of a memory A 11 , B 11 、C 11 、A 12 , B 12 、C 12 , 011, 012, 013, subtractor A 21 , B 21 、C 21 、A 22 , B 22 、C 22 , 021, 022, 023, filter A 31 , B 31 、C 31 、A 32 , B 32 、C 32 , 031, 032, 033, maximum value seeking circuit 041, multiplier A 41 , B 41 、C 41 , 042, adder A 42 , B 42 、C 42 and comparator A 5 , B 5 、C 5 constitute. where memory A 11 , B 11 、C 11 input and the subtractor A 21 , B 21 、C 21 The positive input ends of the transformer Y are respectively input 0 The instantaneous value signal of the three-phase differential current on the side i da i db i dc , memo...
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This invention discloses a longitudinal deviation protection method for a fault component transformer with the largest side zero sequence rate brake, which weights the fault component of the brake current representing the through current and the maximum value in the fault components of the zero sequence currents of the neutral point earth sides of the transformer to get the fault component of the brake current containing zero sequence current, the fault component of which and that of the differential current of a related phase are used to make up of a fault component rate brake element of said phase, when the component of the differential current is greater than that of the brake current containing zero sequence current and greater than the minimum action current, a signal of the fault component rate brake element of said phase is output.
Description
technical field [0001] The invention relates to a relay protection method of an electric power system, in particular to a transformer differential protection method with maximum zero-sequence current fault component ratio braking. Background technique [0002] The current longitudinal differential protection of power transformers consists of components such as differential quick-break, ratio differential, excitation inrush current detection, and over-excitation detection. According to DL / T 684-1999 "Large Generator Transformer Relay Protection Setting Calculation Guidelines", the block diagram of transformer longitudinal differential protection is shown in Figure 1, and the principle wiring example of longitudinal differential protection is shown in Figure 2. Usually using a current transformer for Y 0 Y / Δ transformation is performed on the three-phase current on the side to eliminate the influence of zero-sequence current. Obviously, after the transformation, each current...
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IPC IPC(8): H02H7/045
Inventor 徐习东
Owner ZHEJIANG UNIV