Abstract: Provided is a handcart circuit breaker and a contact device thereof including a contact arm and a moving contact. Inner walls of a cylindrical contact finger base in axial direction respectively have a contact finger groove with a spring contact finger for plugging the contact arm and a fixed contact; a rear of the contact finger base sleeves with a front of the contact arm having a positioning groove larger than a fitting end of the support pin, the contact finger base has support pins extending into the contact finger base; a diameter of a circle corresponding to the fitting end of each support pin is larger than a diameter of a circle corresponding to a bottom of each positioning groove; the contact finger base connects with the contact arm and an elastic support structure is arranged between the contact arm and the inner wall of the contact finger base.

Abstract: The present disclosure relates to a method for preventing a maloperation of differential protection of an optical fiber caused by saturation of a single Current Transformer (CT) of 3/2 connection. By applying a combination of the differential judgment and the sub-CT current judgment, reliable identification of internal and external faults is ensured, and the problem of misjudging of the internal fault as the external fault can be prevented as well.

Abstract: The present disclosure relates to a method for quickly identifying disconnection of a Current Transformer (CT) in protection of a 3/2 connection mode based bus. The present disclosure can quickly and accurately identify the disconnection of the CT, thereby avoiding the problem of a maloperation in protection of a bus caused by the disconnection of the CT.

Abstract: A distributed test method applicable to a system-level test of intelligent high voltage equipment. The method includes: firstly, carrying out unified modeling on test equipment behaviors according to test requirements, and generating a general test case for ensuring accuracy and coordination of test behaviors and test time sequences under various work conditions; then, extracting, according to a feature element of role defining, sequence states of same roles from the general test case, and recombining the sequence states according to an execution sequence so as to form test sub-cases of the roles; finally, executing, by each piece of test equipment, corresponding test sub-cases to achieve cooperative linkage by means of information interaction, so as to accomplish entire process simulation of the test conditions.

Abstract: The present invention relates to a method for generating a current differential protection supernode based on an electrical topology of a regional distribution network, which belongs to the fields of automation of electrical power systems and relay protection. The present invention generates several supernode differential protection elements, i.e., differential protection objects, and backup differential protection elements by circularly using a depth-first search method according to the inputted branch-node associative data table reflecting the electrical topology of the distribution network. the present invention can accurately located and quickly isolate the faults in the distribution network system, reduce the probability of power cut in the non-fault lines, reduce the coverage of power cut, quickly reconstruct and self-heal the distribution network, and solve the effect of the distributed access system on the distribution network protection.

Abstract: The present invention relates to a prevention method of abnormal action protection of UHV regulating compensation transformer with no-load input, the prevention method includes: first determining a value of differential current of regulating compensation transformer, if the value of differential current is smaller than a pre-setting threshold, then, identifying whether an uninterruptible point of differential current waveform meets an pre-setting regulation according to original value of differential current or sampling value of differential difference current, and determining comprehensively whether the regulating compensation transformer is in no-load input or in fault directly with a value of second harmonic content of logic differential current together; if a value of differential current before pre-setting period is larger than the pre-setting threshold, the regulating compensation transformer is diagnosed to have external CT saturation, determining comprehensively whether the regulating compensation tra

Abstract: The invention relates to a method of differential protection in the power distribution networks based on phase difference principles. The method comprises the following steps: collecting the current and voltage signals of each loading switch; calculating phase difference between the corresponding currents at two adjacent loading switches, wherein at least one of the two adjacent loading switches accords with ?I? max>n·?IT+?Idz; tripping the two adjacent loading switches if the phase difference corresponding to the two adjacent loading switches being greater than a threshold then a section between the two adjacent loading switches being determined as a fault section. The method only needs to calculate the phase difference between the corresponding currents at the two adjacent loading switches, and achieves the fault determination according to the phase difference being greater than the threshold.

Abstract: Sampling implementation method and device based on conventional sampling GOOSE trip mode. CPU of master NPI plug-in, after receiving a second pulse, transmits sampling pulse generation time and a transmission enable bit to FPGA of the master NPI plug-in at a fixed interval; after detecting the transmission enable bit, the FPGA of the master NPI plug-in judges whether time of its internal timer is greater than/equal to the sampling pulse generation time, if yes, generates a sampling pulse to FPGA of collection plug-in; after receiving sampling pulse, the collection plug-in carries out A/D sampling, and transmits sampled data to the master NPI plug-in; when detecting that all A/D samplings are completed, the master NPI plug-in transmits data packets to protection CPU plug-in. The device includes an MMI plug-in, a protection CPU plug-in, a master NPI plug-in and a collection plug-in. Protection maloperation is thereby reduced.

Abstract: The present invention discloses an oil-gas separation cylinder, an oil-gas separation device and an oil chromatography. The oil-gas separation cylinder comprises an oil-gas separation cylinder body of which axe extends in direction of up and down, a separating block which separates the oil-gas separation cylinder body into an upper cavity and a lower cavity, an oil-gas separation cylinder piston movably installed in the lower cavity, an oil inlet passage and an oil outlet passage, and an oil-gas separation cylinder vent arranged at upper end of the upper cavity, wherein both of the oil inlet passage and the oil outlet passage are communicated with the upper cavity, wherein the separating block is provided with a guiding hole and a spaying hole used to communicate the upper cavity to the lower cavity, or the separating block is provided with a spaying hole guiding oil used to communicate the upper cavity to the lower cavity.

Abstract: The present invention relates to a method of preventing misoperation about a relay protection device in a smart substation. Reversely operating CPU operation results of two operation records about the relay protection device, in order to form corresponding disassembler codes. According to disassembler codes, calculating similarity of the CPU operation results of the two operation records about the relay protection device by a structured method. Judging whether the similarity is greater than a set threshold or not. If the similarity is greater than the set threshold, the CPU operation results of the two operation records about the relay protection device to be the same, otherwise, the CPU operation results of the two operation records about the relay protection device are judged to be different. The present invention avoids the misoperations of the relay protection device on operation.

Abstract: The present invention relates to a differential protection method for bridge circuit in current converter control system, including the steps of: 1). obtaining sample values of the three-phase current for the current converter control system at AC side thereof, and calculating the absolute value of each sampling value respectively; 2). calculating a value of current at the AC side of the current converter control system; and 3). determining whether to perform a relay protection for the current converter control system according to the value current at the AC side of the current converter control system. The method of the present invention provided, is fast, convenient, and with a small amount of calculation. The current converter control system determines whether to perform a relay protection in a short time. Also it reduces the possibility that the equipment burned because of cannot break the circuit in time.

Abstract: The present invention relates to a centralized and networked protection system and method of regional distribution network, and belongs to the field of electrical system automation and relay protection.

Abstract: The present invention relates to a busbar differential protection method. For each bay, firstly, zero-crossing point of voltage is determined according to sample values of voltage, then the current values are re-sampled on a current fitting curve by using zero-crossing point of voltage as a synchronous signal according to a given sampling time period to get a sample sequence. The sample sequence is comprised of current values of sampling points and sample serial numbers. The sample serial numbers of sampling points at the same time are same for the sample sequence of respective interval. Finally, computing is done to sample sequences of respective intervals, and differential protection is achieved.

Abstract: The present invention relates to a networked differential protection method for a distribution network based on overhauling of terminal equipment. The present invention comprises the steps of detecting in real time an operation state of a terminal equipment, and reconstructing a differential logic when there is a terminal equipment under an overhaul state so as to bring it into a state in which an overhaul mode and an operation mode are in parallel; for the operation mode in the state in which an overhaul mode and an operation mode are in parallel, only calculating data of all nodes in normal operation in an electrical element by a differential protection for the electrical element, while excluding data under the overhaul state in the electrical element from taking part in calculation. With the method of the present invention, the operation switch may be reliably switched off and failures may be isolated when they appear during an experiment of a scheduled test.

Abstract: The present invention relates to a busbar differential protection method. For each bay, firstly, zero-crossing point of voltage is determined according to sample values of voltage, then the current values are re-sampled on a current fitting curve by using zero-crossing point of voltage as a synchronous signal according to a given sampling time period to get a sample sequence. The sample sequence is comprised of current values of sampling points and sample serial numbers. The sample serial numbers of sampling points at the same time are same for the sample sequence of respective interval. Finally, computing is done to sample sequences of respective intervals, and differential protection is achieved.

Abstract: The present invention relates to a centralized and networked protection system and method of regional distribution network, and belongs to the field of electrical system automation and relay protection.

Abstract: The present invention relates to a method for generating a current differential protection supernode based on an electrical topology of a regional distribution network, which belongs to the fields of automation of electrical power systems and relay protection. The present invention generates several supernode differential protection elements, i.e., differential protection objects, and backup differential protection elements by circularly using a depth-first search method according to the inputted branch-node associative data table reflecting the electrical topology of the distribution network. the present invention can accurately located and quickly isolate the faults in the distribution network system, reduce the probability of power cut in the non-fault lines, reduce the coverage of power cut, quickly reconstruct and self-heal the distribution network, and solve the effect of the distributed access system on the distribution network protection.