Abstract: A converter valve includes a top shielding cover, a bottom shielding cover, at least two vertically stacked valve layers, and a maintenance platform. The top shielding cover is disposed at an upper portion of an uppermost valve layer. The bottom shielding cover is disposed at a lower portion of a lowermost valve layer. Each of the valve layers comprises two valve modules disposed side-by-side in a horizontal direction. The two valve modules are electrically connected via a busbar and mechanically connected via securing connectors. A lower valve layer is connected to an upper valve layer in a suspended manner. A body of the maintenance platform is located between horizontal planes on which two vertically adjacent valve layers are located, or between horizontal planes on which the lowermost valve layer and the bottom shielding cover are located.

Abstract: A shell structure for a thyristor trigger unit comprises an integrally-formed shell body with a holder and a cuboid structure, and a side plate. The cuboid structure is a cuboid with an opening in its front where an open face is formed at the front opening of the cuboid. The cuboid further includes a rear panel, a left panel, a right panel, an upper panel, and a lower panel. The holder includes a square retaining plate and two triangular stiffener plates. The square retaining plate is formed by a bottom panel extending towards a side of the left panel in a long side direction of the cuboid while the triangular stiffener plates are fixedly connected between the square retaining plate and the left panel. The side plate is mated with and detachably mounted on the open face to produce a sealed 6-face cuboid structure by sealing off said open face.

Abstract: A converter valve includes a top shielding cover, a bottom shielding cover, at least two vertically stacked valve layers, and a maintenance platform. The top shielding cover is disposed at an upper portion of an uppermost valve layer. The bottom shielding cover is disposed at a lower portion of a lowermost valve layer. Each of the valve layers comprises two valve modules disposed side-by-side in a horizontal direction. The two valve modules are electrically connected via a busbar and mechanically connected via securing connectors. A lower valve layer is connected to an upper valve layer in a suspended manner. A body of the maintenance platform is located between horizontal planes on which two vertically adjacent valve layers are located, or between horizontal planes on which the lowermost valve layer and the bottom shielding cover are located.

Abstract: Disclosed are a modulation method of a modular multilevel converter and a fault isolation method of a submodule unit. The modulation method comprises a first mode and a second mode, and the first mode and the second mode operate cyclically. In the first mode, a first power semiconductor switch and a second power semiconductor switch are turned on alternately, while a third power semiconductor switch is turned off normally and a fourth power semiconductor switch is turned on normally. In the second mode, the third power semiconductor switch and the fourth power semiconductor switch are turned on alternately, while the first power semiconductor switch is turned on normally and the second power semiconductor switch is turned off normally.

Abstract: A thyristor assembly radiator for a DC converter valve. A water discharging port of an Nth radiator is communicated with a water discharging port of an (N?2)th radiator. A water feeding port of the Nth radiator is communicated with a water feeding port of an (N+2)th radiator. Or, a water feeding port of the Nth radiator is communicated with a water feeding port of the (N?2)th radiator, and a water discharging port of the Nth radiator is communicated with a water discharging port of the (N+2)th radiator. A water discharging port of an Mth radiator is communicated with a water discharging port of an (M?2)th radiator, and a water feeding port of the Mth radiator is communicated with a water feeding port of an (M+2)th radiator, or a water feeding port of an Mth radiator is communicated with a water feeding port of the (M?2)th radiator, and a water discharging port of the Mth radiator is communicated with a water discharging port of an (M+2)th radiator.

Abstract: An assembly method for a DC converter valve includes: assembling a top shielding case: lifting the top shielding case to a designated height via a lifting platform, and then fixedly connecting the top shielding case to lower ends of insulators, fixedly connecting upper ends of the insulators to a truss, the truss being located on the top of a valve hall; assembling valve layers: lifting the valve layers to designated locations in a sequence from top to bottom via the lifting platform; and assembling a bottom shielding case: lifting the bottom shielding case to a designated height via the lifting platform, connecting the bottom shielding case to a lowermost valve layer and suspending the bottom shielding case below the lowermost valve layer via suspension insulators. By means of the present invention, the operation is convenient, a small quantity of devices is used, and the security and reliability are high.

Abstract: A unified power flow controller for a double-circuit transmission line comprises at least one parallel-connection transformer, three current converters, at least two series-connection transformers, a parallel-connection side switching circuit, a series-connection side switching circuit and a direct current common bus. The series-connection transformers connected with at least one group of by-pass switches in parallel. The three current converters connected to each loop line in series after being connected with at least one series-connection transformer through the series-connection side switching circuit. The three current converters connected to an alternating current system after connected with at least one parallel-connection transformer through a parallel-connection side switching circuit starting circuit. The three current converters are connected to the direct current common bus through a transfer switch.

Abstract: Provided are a commutation control method and a commutation control apparatus. The method includes: detecting whether transient disturbance in a DC transmission system satisfies a disturbance criterion condition; when the transient disturbance satisfies the disturbance criterion condition, determining a maximum trigger delay angle used in a commutation operation performed by a current converter on an inverter side of the DC transmission system, the determined maximum trigger delay angle being smaller than a maximum trigger delay angle used before the transient disturbance; and controlling the current converter on the inverter side of the DC transmission system to perform the commutation operation based on the determined maximum trigger delay angle.

Abstract: Disclosed are a fault current-suppressing damper topology circuit and a control method thereof and a converter. An anode of a separate diode is connected to a positive electrode of a second switch module, a cathode of the separate diode is connected to one end of an energy storage capacitor, and the other end of the energy storage capacitor is connected to a negative electrode of a first switch module; a damping resistor is connected in parallel with an arrester and then with the first switch module; a bypass switch is connected in parallel between a terminal x1 and a terminal x2 of the damper topology circuit; a power supply system acquires energy from the energy storage capacitor and supplies power to a control system; and the control system controls an operating state of the damper topology circuit by controlling the bypass switch, the first switch module and the second switch module. The fault current-suppressing damper topology circuit is applied to voltage source converters.

Abstract: A signal name based method for automatic signal exchange between multiple embedded CPU boards, includes: dividing CPU boards into master board and slave board, where each slave board sends signal registration information to the master board; reading an exchange relationship between an output signal and an input signal that is represented by a connection line between signal names, calculating and allocating a data bus address to which the output signal and the input signal are mapped, and sending memory addresses, data types, and bus addresses of signals to each slave board; saving these as output signal tables and input signal tables; and writing, by a signal sender, a value of an output signal into a corresponding bus address according to the output signal tables, and reading, by a receiver, a value of an input signal from a corresponding bus address according to the input signal tables.

Abstract: Disclosed in the present invention is a hybrid back-to-back direct current transmission system. The system comprises an LCC converter and a VSC converter in a back-to-back connection, and a first changeover switch, a second changeover switch, a third changeover switch and a fourth changeover switch. The first changeover switch is connected to a first alternating current system and the LCC converter; the second changeover switch is connected to the first alternating current system and the VSC converter; the third changeover switch is connected to a second alternating current system and the VSC converter; and the fourth changeover switch is connected to the second alternating current system and the LCC converter. In forward power delivery, the first changeover switch and the third changeover switch are closed; and in reverse power delivery, the second changeover switch and the fourth changeover switch are closed.

Abstract: A method and apparatus for identifying an open phase of a circuit breaker on the basis of voltage. The method comprises: a protection apparatus measures three-phase voltages at two sides of a circuit breaker; respectively calculates a vector difference and an effective value of the voltages at two sides of the circuit breaker; when the phase voltages at two sides are both greater than 80% to 90% of a rated voltage, and the voltage vector difference at two sides of the one-phase or two-phase circuit breaker is greater than a set voltage, it is determined that the circuit breaker has an open phase; and actuates an alarming or tripping operation after a short time delay t.

Abstract: A tripolar VSC-HVDC system and method include a rectifier and an inverter formed by a three-phase six-bridge arms modular multilevel converter (MMC) respectively, and two converter valves are arranged on the DC side of the rectifier and inverter respectively. The midpoint of upper and lower converter valves of the rectifier and inverter are connected with a pole 3 DC line by a smoothing reactor. Triggering of the upper and lower converter valves is controlled to change the DC voltage polarity of the pole 3 periodically, and tripolar DC transmission is realized by modulating current orders of the three poles.

Abstract: A low-frequency band suppression enhanced anti-reversal power system stabilizer is presented by the invention. Currently the widely used PSS2B power system stabilizer needs lead elements above Order 2 to meet the phase compensation requirement of DC blocking signal of active power, thus quickly increasing high-frequency band gain, restricting allowable total setting gain of PSS, limiting low-band gain and reducing low-frequency band suppression ability of power system stabilizer. The invention will add generator speed signal ? (which is treated by DC blocking element and corrected by parallel proportional differential PD) and active power signal Pe (which is treated by DC blocking element and gained by gain factor Ks3) to get equivalent synthetic mechanical power of power system stabilizer.

Abstract: A submodule distributed control method, device and system are provided. Submodules of each bridge arm are grouped. Each group corresponds to one valve based controller. An upper-level control device calculates a weight of each group according to a bridge arm current, an average voltage of normal submodules in each group, and the number of the normal submodules in each group; calculates, according to the number of submodules to be input in a corresponding bridge arm, the number of submodules being input in each group and delivers the number to the valve based controller. The valve based controller operates according to a voltage balancing policy and a gating method that are provided in the prior art.

Abstract: The present invention discloses a direct current (DC) voltage control method. The present invention further discloses an apparatus for implementing the method. With the present invention, DC voltage oscillation of a system, which is caused when a DC voltage primary control station stops running, may be reduced.

Abstract: Provided are a commutation control method and a commutation control apparatus. The method includes: detecting whether transient disturbance in a DC transmission system satisfies a disturbance criterion condition; when the transient disturbance satisfies the disturbance criterion condition, determining a maximum trigger delay angle used in a commutation operation performed by a current converter on an inverter side of the DC transmission system, the determined maximum trigger delay angle being smaller than a maximum trigger delay angle used before the transient disturbance; and controlling the current converter on the inverter side of the DC transmission system to perform the commutation operation based on the determined maximum trigger delay angle.

Abstract: The present invention provides a method for inhibiting multiple inverter stations from entering a passive control mode in an island state. The method includes dividing inverter stations into groups in advance; a principle for group division is dividing inverter stations whose alternating-current sides are connected to each other through an alternating-current line in a normal running condition into a group; priorities of the inverter stations are preset in each group to tune relevant fixed values of the inverter stations for island detection; a tuning principle is that an inverter station with a higher priority has a more sensitive relevant fixed value, and an island state is more easily detected for the corresponding inverter station; an inverter station for which an island state is detected can enter a passive control mode only when all the other inverter stations with priorities higher than the priority of the inverter station in the group send enabling signals.

Abstract: A submodule distributed control method, device and system are provided. Submodules of each bridge arm are grouped. Each group corresponds to one valve based controller. An upper-level control device calculates a weight of each group according to a bridge arm current, an average voltage of normal submodules in each group, and the number of the normal submodules in each group; calculates, according to the number of submodules to be input in a corresponding bridge arm, the number of submodules being input in each group and delivers the number to the valve based controller. The valve based controller operates according to a voltage balancing policy and a gating method that are provided in the prior art.

Abstract: Disclosed are a resistor, a heat dissipater and a combinatory device of the resistor and the heat dissipater, and relates to the field of power electronics. The resistor is cylindrical, and comprises a metal end, an insulating part, a casing, metal bars, a resistor wire, thermally conductive insulating fillers and a metal connection mechanism. The metal connection mechanism of the resistor and the heat dissipater are connected by means of direct contact. The structure and the connection method can shorten the length of the resistor, completely insulate the electrical circuits of the resistor from the possible leakage of the water inlet- and outlet-pipe of the heat dissipater, and enable the combinatory device of the resistor and the heat dissipater to be structurally more compact and the connections thereof cleaner.