A method of clearing a fault in a high voltage DC electrical network, including power converters interconnected by a DC power transmission, comprising: detecting a fault in the DC power transmission and reconfiguring each power converter to a fault blocking mode drinving the DC fault current towards zero; locating the fault and isolating a faulty portion from a healthy remaining portion; reconfiguring one of the power converters designated as a re-energising power converter from the fault blocking to re-energise the healthy remaining portion; and detecting a rise in the voltage level in the healthy remaining portion above a threshold level and reconfiguring the remaining power converter connected with the healthy remaining portion from the fault blocking to the normal power transmission.

The invention relates to a two-way electrical power distribution network including: a high electrical power distribution bus; medium voltage electrical power feed lines; low voltage distribution lines, wherein the low voltage distribution lines are connected to load(s) and/or source(s); and, medium voltage electrical power regulating apparatus including: a DC contactor having DC terminals; a transmission network connector connected to the medium voltage electrical power feed line including: live terminal(s) connected to live connection(s) and a neutral terminal connected to a neutral of the medium voltage electrical power feed line; switches connected to the DC contactor; and electronic controlling devices coupled to the switches and control the switches to independently regulate electrical power on each of the live connection and the neutral connection of the medium voltage electrical power feed line to thereby maintain a voltage in the electrical power distribution bus during different load and source conditions.

An active two-terminal inductor device with a controllable inducitance based on an inductance value input L_I. A processor system PRS executes an algorithm which controls a power converter PCV with controllable electric switches connected to the two external terminals A, B along with a fixed value inductor component L1. Based on sampling of at least a voltage or a current in connection with the inductor component L1, the algorithm controls the power converter PCV to provide a resulting inductance across the external terminals A, B which serves to match the inductance value input L_I.

The present invention relates to an apparatus and a method for synchronizing a clock of VBE in a HVDC system capable of increasing reliability by synchronizing the clock of the VBE in the HVDC system to suppress harmonic generation and generate duplicate clock to supply stable clock to submodules. The apparatus for synchronizing the clock of the VBE in the HVDC system comprises an operation board for creating a reference clock and an interface board for controlling submodules on or off being synchronized to a reference clock.

There is provided an electrical assembly comprising a converter (20) for connection to an electrical network (40), the converter (20) comprising at least one module (44) including at least one switching element (46) and at least one energy storage device (48), the or each switching element (46) and the or each energy storage device (48) in the or each module (44) arranged to be combinable to selectively provide a voltage source, the electrical assembly including a controller (54) configured to selectively control the switching of the or each switching element (46) in the or each module (44), wherein the electrical assembly includes a sensor (56a) configured for measuring a current of the electrical network (40), wherein the controller (54) and sensor (56a) are configured to operate in coordination to carry out a characterisation of an electrical parameter of the electrical network (40) so that, in use: the controller (54) selectively controls the switching of the or each switching element (46) in the or each module (44) to modify an electrical parameter of the converter (20) so as to modify the current of the electrical network (40); the sensor (56a) measures a resultant modified current of the electrical network (40); and the controller (54) processes the measured resultant modified current of the electrical network (40) so as to characterise the electrical parameter of the electrical network (40).

One circuit includes first and second primary terminals for connection to first and second power transmission lines and a current transmission path extending between the primary terminals and having current transmission path portions separated by a third primary terminal. A first current transmission path portion includes at least one primary switching element connected in series between the first and third primary terminals, the second current transmission path portion includes an energy conversion block connected between the second and third primary terminals, and the energy conversion block includes at least one primary energy conversion element for removing energy from the power transmission lines. The control circuit further includes a converter limb connected across the second and third primary terminals that includes an auxiliary converter. The control circuit further includes a control unit which controls the auxiliary converter to selectively provide a voltage source.

Disclosed are a voltage source converter based high voltage direct current (VSC-HVDC) high-frequency resonance suppression method, system, and device. The method includes: when an effective value of an actually input alternating current (AC) voltage is reduced from a normal value to meet a preset condition, making the virtual electrical quantity completely equal to the actual electrical quantity, and performing full real-time tracking for the actual electrical quantity to improve dynamic characteristics of a power system at the moment of a fault; and after performing the full tracking for a period of time, if the effective value of the actual AC voltage is less than a preset threshold, performing adaptive tracking until the actual electrical quantity recovers to a stable value. The present disclosure can reduce a risk of high-frequency resonance of a VSC-HVDC, avoid deteriorating dynamic characteristics of the VSC-HVDC, and improve safety of fault ride-through of the VSC-HVDC.

The present invention discloses an LCC and MMC series-connected HVDC system with DC fault ride-through capacity, comprising rectifier and inverter linked by DC transmission line; Both the positive pole and the negative pole of the rectifier and the inverter consist of line-commutated converter and modular converter in series-connection; the modular converter adopts one MMC or several parallel-connected MMCs. The present invention has the advantage of low cost, low power loss and high reliability of the LCC, as well as flexible control, low harmonics and AC voltage support of the MMC. Further, the present invention is able to deal with DC fault by itself, hence additional DC fault clearing equipment is not needed. As a result, the present invention is suitable for the field of long-distance large-capacity power transmission and has broad development potential.

The present invention provides a high voltage regulated DC power supply with full range 24 pulse input for ripple free output for high power RF amplifier, comprising: full range 24 pulse 3 phase 11 kV input system configured to provide uncontrolled low voltage DC bus, low input harmonics and high input power factor; a plurality of DC-DC power modules having their output connected in a series and coupled to the said DC bus voltage; each power module comprising a DC source, an inverter bridge IGBTs operating at predefined duty cycle and staggered to reduce the output ripple and output stored energy; and a combination of feed forward and feedback control circuit adapted to regulate the variations in the input line voltage and the variation in output at various load current to finally obtain ripple free high voltage output.

A high voltage direct current (HVDC) transmission system is provided. The high voltage direct current (HVDC) transmission system includes a rectifier converting alternating current (AC) power into DC power; an inverter converting the DC power into the AC power; DC transmission lines W1 and W2 transmitting the DC power obtained from the rectifier through conversion to the inverter; a first active power measurement unit measuring first active power input to the rectifier; a second active power measurement unit measuring second active power output from the inverter; and a first control unit controlling the operations of the rectifier and the inverter based on the first active power measured and the second active power measured, wherein the first control unit senses oscillation generated in the HVDC transmission system and generates a control signal for damping the sensed oscillation to control one or more of the rectifier and the inverter.