There is provided a power supply apparatus for supplying power to an external electrical load, including a power transmission line or cable through which an alternating or direct current may flow, a power supply module, a control unit, an output terminal for connection to the external electrical load, and a converter. The power supply module includes an input terminal connected to the power transmission line or cable, and includes switching elements and energy storage device(s). The control unit controls the switching elements to selectively switch each energy storage device into circuit to direct a current flowing in the power transmission line or cable to flow through each energy storage device so as to store energy to form a power source. The converter draws power from the power source and supplies the drawn power to the output terminal.

A dynamic stability analysis and control method for a voltage sourced converter based high voltage direct current (VSC-HVDC) transmission system. The method includes the following steps: unlocking a converter station of the VSC-HVDC transmission system to make the VSC-HVDC transmission system run in a non-island control mode; extracting corresponding parameters of the VSC-HVDC transmission system, wherein the parameters include an effective voltage value U.sub.t0 of an AC system, an outgoing reactive power Q.sub.vsc0 of the VSC-HVDC transmission system, a gain k.sub.p of a phase-locked loop (PLL), and a proportional integral time constant k.sub.i of the PLL; calculating a short-circuit ratio (SCR), an unit value of U.sub.t0 and an unit value of Q.sub.vsc0; calculating a key stable component; checking the sign of the key stable component to determine the stability of the VSC-HVDC transmission system.

In the field of high voltage direct current (HVDC) power transmission networks there is a need for an improved power converter.

A power converter, for use in a HVDC power transmission network, comprises first and second DC terminals, for connection in use to a DC network and between which extends at least one converter limb. The or each converter limb includes first and second limb portions which are separated by an AC terminal, for connection in use to an AC network. Each limb portion includes a switching valve, and the power converter including a controller programmed to control switching of the switching valves to control the flow of a converter current (I.sub.max) through the power converter and thereby in-use transfer power between the power converter and the AC network. The power transferred between the power converter and the AC network has an active component and a reactive component. The controller is further programmed in use to: (i) prioritize to a first extent the transfer of reactive power between the power converter and the AC network during a first operating condition, when the AC voltage (V) of the AC network lies outside a desired operating range, by allowing up to a first amount of the converter current (I.sub.max) to be a reactive current; and (ii) prioritize to a second extent, less than the first extent, the transfer of reactive power between the power converter and the AC network during a second operating condition, when the AC voltage (V) of the AC network lies within the desired operating range, by limiting the amount of converter current (I.sub.max) that can be a reactive current to a second amount, less than the first amount, the second amount being determined according to a measured operating frequency of the AC network.

The disclosure discloses a commutation failure prediction method, device and storage medium based on energy accumulation features of inverter. The method includes the following steps: collecting instantaneous values of three-phase valve side current and calculating the derivatives of the three-phase valve side current according to the instantaneous values of three-phase valve side current; the derivative includes positive, negative and zero states; according to the derivatives of the three-phase valve side current, determining the locations of incoming valve and ongoing valve; based on the valve side current of the incoming valve and ongoing valve, calculating energy accumulation features of the 12-pulse inverter; predicting whether the commutation failure from the incoming valve to the ongoing valve will happen according to the states of the derivatives of the three-phase valve side current and the energy accumulation features of the 12-pulse inverter.

The disclosure relates to a method and system for evaluating the stability of HVDC receiving end system and storage medium, which relates to the technical field of high voltage direct current transmission. The method includes: collecting voltage at a generator port, current at the generator port and rotational speed of the generator after eliminating fault; determining a corresponding relationship between the generator dynamic energy and the time according to the voltage at the generator port, the current at the generator port and the rotational speed of the generator; determining the attenuation intensity of the generator dynamic energy according to the corresponding relationship between the generator dynamic energy and the time; determining stability of the HVDC receiving end system according to the attenuation intensity of the generator dynamic energy.

A method of operating a thyristor-based line-commutated multi-phase power converter on a multi-phase AC voltage connection point, which is supplied by an AC voltage network. Between the AC voltage connection point and an AC voltage connection of the power converter, a series circuit of modules is arranged for each phase. Each of the series circuits has a first electronic switching element, a second electronic switching element, and an electric energy storage device. The voltages of the phases of the AC voltage connection point are measured and, if an undervoltage is detected on a phase of the AC voltage connection point, an additional voltage adding to the voltage of that phase is generated by way of the series circuit of modules allocated to that phase in such a way that the voltage of that phase is increased, at least temporarily.

A modular HVDC platform and a method for constructing the same are disclosed herein. The modular HVDC platform has a topside disposed on a structural jacket. The topside includes a first rectifier module, a second rectifier module, and a utility module. The first and second rectifier modules have equipment for converting AC power to DC power disposed therein. The utility module contains equipment for supporting the operations of the rectifier modules. Each of the rectifier modules and the utility modules can be fabricated and commissioned onshore prior to installation on the structural jacket at an offshore location.

A converter station has two line-commutated converters for energy transmission via a bipolar high voltage direct current transmission line. In a first operating mode of the converter station the two converters are electrically connected in an anti-parallel circuit to the same pole of the high voltage direct current transmission link and one of the converters is operated as a rectifier and the other converter is operated as an inverter in an network. In a second operating mode the two converters are connected to different poles of the high voltage direct current transmission link and both converters are operated as either rectifiers or inverters in the AC network. In both operating modes a station active power exchanged between the converter station and the AC network is controlled by active power specifications for converter active powers which are exchanged between the converters and the AC network.

Pulse power supply systems and methods are disclosed. A method includes providing earth-ground-referenced control circuitry and providing floating pulsed-power circuitry. The method also includes providing a DC offset voltage to the return port of the pulsed-power circuitry with a DC offset module and providing a peak voltage to the pulsed-power circuitry with a DC voltage source. Power is applied from a power source of the control circuitry to a driver of the pulsed-power circuitry via a galvanically-isolating power path and a trigger signal is applied from the control circuitry to the driver via a galvanically-isolated signal path to prompt the driver to produce a driver signal. A voltage pulse is produced between the output port and the return port by closing the switch with the driver signal to couple the peak voltage to the output port.

A normal workflow including a plurality of steps may be defined by exemplary systems and methods for use in preparing a treatment, performing a treatment, and performing post-treatment processes. A user may be guided by one or more workflow affordances to indicate where and how to use a graphical user interface to follow the normal workflow. When a user deviates from the normal workflow, one or more deviation workflow affordances may be displayed on the graphical user interface to guide a user back to the normal workflow.