An Adaptive Calibration Method for Grounded Busbar Differential Protection
A busbar differential protection and correction method technology, which is applied in the direction of emergency protection circuit devices, electrical components, etc., can solve the problems of increasing protection misoperation, the secondary circuit of state identification signal or unreliable judgment logic, etc., so as to avoid protection misoperation , Prevent misoperation of protection and improve the effect of correctness
Active Publication Date: 2018-11-23
GUANGZHOU BUREAU CSG EHV POWER TRANSMISSION
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Problems solved by technology
[0007] In actual operation, due to unreliable factors in the secondary circuit or judgment logic of the state identification signal, in the normal operation mode of the system, once the state identification signal is lost (for example, it should be set to 1, but it is actually set to 0 by mistake), Then the differential current algorithm of the grounding pole bus differential protection will not match the actual operating state of the system, which instead increases the probability of protection misoperation
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Embodiment 1
[0045] Specifically, the adaptive correction method for the differential protection of the ground electrode bus proposed by the present invention includes the following steps:
[0046] S1, to determine whether there is a differential current in the grounding electrode bus differential protection. The adaptive correction method is not suitable for the situation where the system fails and the state identification signal is lost. The description of the following schemes is based on the situation when the system is running normally. .
[0047] S2, if the judgment is yes, obtain the differential current I diff and compare the differential current I diff The absolute value of and the preset current threshold Δ. where the differential current I diff Calculate according to the following formula:
[0048] I diff =||IdLN-S 1 ×IdLN_op|-|S 2 ×IdLH_op-S 3 ×(Idee1+Idee2)-S 4 ×IdSG||
[0049] S 1 , S 2 , S 3 and S 4 IdLN is the neutral bus current of the local pole, IdSG is th...
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The invention relates to an adaptive correction method of grounding electrode bus-bar differential protection. The method includes the following steps that: whether differential current exists in the grounding electrode bus-bar differential protection is judged; if differential current exists in the grounding electrode bus-bar differential protection, differential current Idiff is obtained, the absolute value of the differential current Idiff is compared with a preset current threshold value delta; and when the absolute value of the differential current Idiff is greater than the current threshold value delta, the method enters correction logic, an unbalanced branch circuit is judged through the state characteristics of grounding electrode bus-bar differential protection state identification signals under different operating conditions of a direct-current transmission system, and therefore, correction processing is performed on the unbalanced branch circuit. Based on logic judgment and current correction on the unbalanced branch circuit, current characteristic recognition-based differential current adaptive correction is realized when the state identification signals are missing, so that the real operation state of the system can be effectively recognized, and protection malfunction caused by current injection work performed in electrode maintenance can be avoided, and protection malfunction caused by state identification signal loss can be avoided, and the correctness of direct-current protection can be improved.
Description
technical field [0001] The invention relates to the technical field of high-voltage direct current transmission, in particular to an adaptive correction method for differential protection of a ground electrode busbar. Background technique [0002] In the HVDC protection system, the grounding pole bus differential protection is mainly used to detect faults in the grounding pole bus and related protection ranges. Since the HVDC power transmission system has various operating modes such as BP (bipolar operation), GR (single pole ground return line) and MR (unipolar metal return line), in order to prevent the Mistakenly tripping running poles and grounding poles bus differential protection introduces the state identification signal as an auxiliary criterion. When the operating state of the system changes, the state identification signal is set through logical judgment and corresponds to the actual operating state of the system one by one, so that the relevant measurement quanti...
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IPC IPC(8): H02H7/22
CPCH02H7/226
Inventor 罗宇航林康照李兴罗敬华郭卫明陈浩
Owner GUANGZHOU BUREAU CSG EHV POWER TRANSMISSION