Abstract: This present inversion relates to a detection system and detection method of distributed generation islanding based on power frequency carrier. The system includes a power frequency carrier signal generating device near the terminal power distribution substation, a power frequency carrier signal detection device in distributed power grid; the power frequency carrier signal generating device is connected to the substation bus through a signal coupling transformer; the power frequency carrier signal generating device is connected with signal coupling transformer though phase A, B C live wires and the N middle wire, that results in the signal can be send by anyone signal phase, any two phases parallel way or three phases parallel way. The power frequency carrier signal detection device is connected with the low voltage power network though phase A, B and C live wires and the N middle wire.

Abstract: The present invention relates to a real time dynamic physics simulation device of flexible DC transmission system. The device includes simulated converter transformer, simulated AC field, simulated DC field, simulated converter reactor, simulated converter, and measurement and control cabinet chassis; the simulated AC field includes the vacuum switch I, the contactor I, resistors and the vacuum switch II connected orderly; the simulated DC field includes successively connected the vacuum switch contactor III and II; the simulated AC field is connected with said measurement and control cabinet chassis; Said converter transformer is set between said resistors and said vacuum switch II; Said simulated converter reactors and said simulated converter connected are set between the vacuum switch II and the vacuum switch III.

Abstract: The present invention provides a method and an apparatus for determining separation efficiency of a cyclone separator. The method comprises: collecting solid particles separated by a cyclone separator; performing a particle size analysis for the collected solid particles; calculating feature parameters of the collected solid particles according to a result of the particle size analysis, wherein the feature parameters are values representing particle size and particle size uniformity of the solid particles; and determining a separation efficiency corresponding to the feature parameters of the collected solid particles as a separation efficiency of the cyclone separator, according to a predetermined correspondence between feature parameter and separation efficiency. The present invention avoids the difficulty in directly measuring the material concentrations at the inlet and the outlet of the cyclone separator and has a small interference with the apparatus.

Abstract: The present invention relates to valve current control method based on modular multi-level converter, this method includes the control of the low frequency oscillations of the current and that of double frequency harmonic component; For said low frequency oscillations of the current, the control method includes some steps as below: first, calculate the half of the sum of the upper arm current and the lower arm current, it is the valve DC current component, said DC current component is arm circulating current; Secondly, comparing the actual value of the arm circulating current to setting value of that, the error is obtained, after some signal processing, additional output set voltage is obtained.

Abstract: The invention relates to Modular multilevel converter valve protection method, the modular multilevel converter valve consists of 6 arms, the arm includes sub modules, 1 arm is controlled by 1 control host, 6 control hosts is controlled by 1 summary control host, the method of the invention includes that the arm realizes locking sub module, bypass sub module, trip requests and system switching request and the summary control host implements summary and control response. The invention improves the reliability of two protection system through the use of dual redundancy protection method, clears the protection division through the layered protection frame of the upper summary control host and multi arm control host. And finally, it improves the whole safety and reliability of the modular multilevel converter valve.

Abstract: The present invention relates to Voltage balancing control method for modular multilevel converter is characterized that, it includes some steps as follows: 1) Determine the leg current direction is positive or negative; 2) Find out the highest sub module on output state whose capacitor voltage amplitude is the maximum, and find out that on bypass state whose capacitor voltage amplitude is the minimum; 3) Determine whether the sub module inputs or bypass operation; this method avoided switching arbitrariness of the sub module, and decreased the switching frequency of the sub module. The capacitor voltage balancing control of the sub module proposed by the method is more suitable to be applied in the field of high voltage and large capacity converter that has large numbers of sub modules.

Abstract: The present invention relates to a basic function unit of voltage source converter, which is characterized in that the basic function unit includes a switching device function module, a by-pass function module, a switch protection function module, a secondary control and protection function module, and a energy storage unit. The secondary control and protection function module, the energy storage unit and the by-pass function module are all fixed on the motherboard, there is a slide rail at the bottom of the motherboard, the motherboard can move back and forth on the slide rail. The voltage source converter based on that unit is highly modular, insensitive to switch device parameters, lower output voltage change rate, and smaller dv/dt stress of equipment, smaller noise, without filter, convenient installation and maintenance.

Abstract: This present inversion provides a digital closed-loop fiber optical current sensor. The modulation signal of the optical wave “phase modulator” of the fiber optical current sensor system is modulation square wave, signal processing system extracts any harmonic wave of the photoelectric converter output modulation square waves, and extracts the measured current information from it. The preamplifier of signal processing system is transimpedance amplifier TIA, the bandwidth is extracted 1/650 instantaneous amplitude square wave directly from the modulation square wave (existing), thus the thermal noise of the preamplifier output and shot noise level is reduced to the existing technology of below 1/650; the current-voltage gain of transimpedance amplifier TIA does not depend on the feedback network resistance, thus it can have high current-voltage conversion gain and use low resistance in the feedback network TIA at the same time.

Abstract: A current sensor for measuring the inhomogeneity of potential distribution of an arrester having a metal casing, a protection circuit of sampling resistor, a signal conditioning circuit, a signal acquisition circuit, an electro-optical conversion circuit, and a battery module. The signal acquisition circuit includes MSP430F149 micro controller unit having an A/D converter and a serial port. The current sensor is an active sensor, works in a high floating potential, and has a good real time response, high accuracy, low power consumption, good electromagnetic compatibility, and strong anti-interference capability even under harsh electromagnetic conditions.

Abstract: This invention provides a high voltage thyristor valve multi-injection test method, it can meet one way valve and double valve operation test and over current test requirements. It has high equivalence and good flexibility. It includes FACTS double way thyristor valve and normal direct current thyristor valve operation tests and over current test. This method is novel, flexible, can carry out many different test and their mixture test and including the high voltage thyristor valve different tests.

Abstract: The present invention relates to a test equipment of direct current thyristor valve, and particularly relates to a fault current test equipment of direct current thyristor valve. This present invention equipment includes high voltage low current circuit and low voltage high current circuit, said test equipment includes fault current circuit, said fault current circuit includes resonant circuit, said high voltage low current circuit, low voltage high current circuit and fault current circuit are all connected with the thyristor sample Vt respectively. In his present invention, the thyristor sample is first heated through the high voltage circuit and low voltage high current circuit to reach the stable state. And then shut off the switch and carries out the test using the fault current which is produced by the fault current circuit. This prevents the power system from the short-circuit impact.

Abstract: A partial discharge test power supply system for an extra high voltage transformer comprises: an electric motor (1); an intermediate frequency generator (2) driven by the electric motor and outputting an intermediate frequency voltage; a middle transformer (9) receiving the intermediate frequency voltage and outputting a test voltage to be applied to a test sample (11) by a generator outlet (5); a low-voltage compensating reactor (8) connected between the intermediate frequency generator and the middle transformer; a high-voltage compensating reactor (10) connected between the middle transformer and the sample; wherein the electric motor and the intermediate frequency generator are arranged in a metal housing (100).

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 invention relates to a self-cooled thyistor device for ultra-high voltage fault current limiter. a self-cooled thyristor valve, it adopts horizontal structure consisted by frames, frames is divided into upper and below two spaces by crossbeams, the bottom of frames is supported by insulators. There is a cross plate between two vertical said frames, the cross plate mounts resistors connect with a high potential plate and capacitor through two wires. There is a thyistor string in said frame upper space, which is constituted of thyistors and cooler series. The thyistor string is compressed tightly by press-fit mechanism, thyistor string crosses current transformers. There are high potential plates on both sides of the thyistor, the number of the potential plates is equal to that of thyistor. One side of the high potential plates links frames, said current transformers connects with high potential plates.

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.

Abstract: The present invention provides a novel direct current thyristor valve saturated reactor includes: case, winding in the case, iron cores, cooling fins, pipes and press fit mechanism. The iron cores are coupled with winding. The invention having the following advantages: simple, modular design, low connection capacity of the wingding, fixed dimension, winding and irons well-cooled, small noise and vibration. The saturated reactor is particularly suitable used as the positive saturated reactor for high voltage current thyristor valve.

Abstract: This invention provides a high voltage thyristor valve multi-injection test method, it can meet one way valve and double valve operation test and over current test requirements. It has high equivalence and good flexibility. It includes FACTS double way thyristor valve and normal direct current thyristor valve operation tests and over current test. This method is novel, flexible, can carry out many different test and their mixture test and including the high voltage thyrsor valve different tests.

Abstract: This present provides a control and protection equipment system suitable for synthesis converter operation test, relates to power system automation equipment field. This system includes human-machine interface element, synchronization element, signal acquisition element, data aggregation element, conditioning element, protecting element, wave form recording element, wave form monitor element, on-off input element, on-off output element, vale based element (VBE), high direct current supply power system controller, high voltage supply system controller, current surge circuit controller, impulse circuit controller, test converter valve water cooling controller and test equipment water cooling system controller. This system can control converter samples and auxiliary valves on set trigging timing, produce various operation tests need heat, voltage and current of the converter samples and carry through operation tests.

Abstract: The present invention relates to a test equipment of direct current thyristor valve, and particularly relates to a fault current test equipment of direct current thyristor valve. This present invention equipment includes high voltage low current circuit and low voltage high current circuit, said test equipment includes fault current circuit, said fault current circuit includes resonant circuit, said high voltage low current circuit, low voltage high current circuit and fault current circuit are all connected with the thyristor sample Vt respectively. In his present invention, the thyristor sample is first heated through the high voltage circuit and low voltage high current circuit to reach the stable state. And then shut off the switch and carries out the test using the fault current which is produced by the fault current circuit. This prevents the power system from the short-circuit impact.

Abstract: This present invention provides a high power electronic device which is used for transforming the alternating current into the direct current, or transforming the direct current into the alternating current: a thyristor valve module, there are two same thyristor valve segments in the whole thyristor valve module; each segment includes saturated reactor, thyristor valve unit, direct current equalizing resistor unit, acquiring energy unit, damped resistor unit, damped capacitor unit, gate series unit and water cooling system. This device series connects the thyristor valves to meet different transmission powers and different voltage ranks. This device is the key element of the high voltage direct current transmission. It can be used for different voltage ranks AD transmission system and can also be used for different voltage ranks DC system, including the ultra-high voltage 800 kV and above system.