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: A method, apparatus and system for suppressing low frequency oscillation in a power system. The method comprises: determining a system transfer function of an interconnected power system section in which a variable frequency transformer (VFT) is located; determining a damping controller parameters according to the system transfer function; and suppressing low frequency oscillation of the power system by means of the VFT based on the damping controller parameter. The objects of the method, apparatus and system are definite: optimizing the damping controller parameter can be achieved by simply tracking and analyzing the response of the system to disturbance, without the need to understand the configuration and parameters of the system or solve complicated power system equations, which has a better effect in suppressing low frequency oscillation in the power system and is advantageous for improving the safety and stability level of the power grid.

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.

Abstract: The present invention relates to an IEEE1588 protocol negative testing method, comprises steps of: connecting a IEEE1588 tester and a slave clock DUT to establish a real-time closed-loop feedback mechanism; taking the IEEE1588 tester as a master clock, and establishing a stable time synchronization with the slave clock DUT; obtaining the timing offset or path delay of the slave clock DUT before disturbance; assembling an abnormal message in a frame and sending it to the slave clock DUT; calculating the timing offset or path delay increment after disturbance of the abnormal message; determining whether there is a sudden change in the timing offset or path delay of the slave clock DUT, wherein if there is no sudden change, the test passes; otherwise the test fails.

Abstract: Connection methods for UHVDC transmission at rectification side and at inversion side, UHV converter stations at rectification side and at inversion side, and an UHVDC transmission system are disclosed. The present invention employs a manner of multiple drop points to solve the problem of poor security stability of electric grid caused by feeding a large amount of power via one point.

Abstract: Disclosed is a pretreatment method for improving antioxidation of steel T91/P91 in high temperature water vapor, which includes applying a slurry, containing rare earth oxide, on a surface of a substrate; holding the temperature in a gas mixture environment of inert gas and water vapor after drying; and cleaning away the solid powder left by the slurry on the surface, thereby obtaining the substrate with a surface rich in chromium and having a small amount of rare earth oxide. As a result of the method, the antioxidation capability of steel T91/P91 in the 500-750° C. water vapor environment can be improved, and films rich in chromium oxide can be formed on the surface of steel T91/P91.

Abstract: A smart home network comprises a plurality of appliances, each of which comprises a unique radio frequency identification tag. The smart home network further comprises a plurality of power outlets, each of which has a unique ID. The power outlets of the smart home network are capable of detecting the RFID tag and measuring the operational parameters of the appliances. The power outlets are further coupled to a central controller. The central controller receives operational parameters of the appliances from the power outlets, constructs a real time model of the smart home and forwards analytical results to a display terminal.

Abstract: A central controller of a micro-grid system is configured to receive the operational parameters of the main grid system and the micro-grid system, update a power generation plan of the micro-grid system based upon the operational parameters of the micro-grid system, wherein the power generation plan is formulated such that power outputs of the micro-grid system approximately match loads of the micro-grid system. Furthermore, the central controller forwards the power generation plan to the plurality of local controllers coupled to the micro-grid system so that the micro-grid system is able to have a seamless transition from a grid-connected mode to a grid-disconnected mode.

Abstract: A micro-grid controller comprises a sampling unit, a processor and an input and output unit. The processor generates a micro-grid operation control command based upon the system operational parameters detected by the sampling unit. Through the input and output unit, the micro-grid controller is able to disconnect the micro-grid system from a main grid system by turning off a switch coupled between the micro-grid system and the main grid system.

Abstract: The present disclosure discloses a suspension insulator and a suspension insulator group. The suspension insulator comprises a silicone rubber umbrella string and a fiber-reinforced resin-based composite rod, wherein the silicone rubber umbrella string is arranged on the fiber-reinforced resin-based composite rod. Since the umbrella string is made of silicone rubber and is arranged on the fiber-reinforced resin-based composite rod, as compared with porcelain suspension insulator or glass suspension insulator, it has a low density and a light weight, and may reduce the load of the tower and is convenient to install and remove. The suspension insulator provided by the present disclosure is especially applicable to the field of power transmission.

Abstract: A method and a device for limiting secondary arc current of an extra-high voltage/ultra-high voltage double circuit line on the same tower. The method comprises the following steps: determining the type of a single-phase-to-ground fault when the extra-high voltage/ultra-high voltage double circuit line on the same tower has a single-phase-to-ground fault (S501); selecting a reactance value of a neutral grounding reactor according to the type of the single-phase-to-ground fault (S502); and switching the extra-high voltage/ultra-high voltage double circuit line on the same tower to the selected reactance value of the neutral grounding reactor (S503). Thus the reactance value of the neutral grounding reactor is not constant, but is changed along with the operating conditions of the power transmission line, that is, the reactance value of the neutral grounding reactor is controllable.

Abstract: The present disclosure discloses a voltage source for calibrating a fast transient voltage measurement system, comprising a DC high voltage power supply, a discharging gap, a high voltage conductor and an earthing conductor, wherein the high voltage conductor and the earthing conductor are high voltage insulated from each other and form a traveling wave line with constant wave impedance; the DC high voltage power supply is connected between the ends of the high voltage conductor and the earthing conductor; the discharging gap is connected between ends of the high voltage conductor and the earthing conductor; the discharging gap is broken down when the charging voltage on the high voltage conductor is risen to a certain amplitude.