Abstract: A method of controlling a power converter in a power transmission network. A first amplitude limit value for a first AC current output from an AC side of the power converter is received. A second amplitude limit value for a negative phase sequence component of the first AC current is received. The negative phase sequence component is measured to provide a measured second amplitude. The negative phase sequence component is regulated to flow with a second amplitude that is the lesser of the measured second amplitude and second amplitude limit value. A positive phase sequence component of the first AC current is regulated to flow with an amplitude not exceeding a regulated third amplitude. The third amplitude is set using a function such that the second amplitude and the third amplitude provide a first amplitude for the first AC current that is substantially equal to the first amplitude limit value.

Abstract: An electrical assembly including a converter for connection to an electrical network, the converter including at least one module having at least one switching element and at least one energy storage device, the switching element and the energy storage device arranged to be combinable to provide a voltage source, the electrical assembly including a controller configured to control the switching of the switching element, wherein the electrical assembly includes a sensor configured for measuring a current of the electrical network, wherein the controller and sensor are configured to carry out a characterization of an electrical parameter so that, in use the controller controls the switching of the switching element to modify an electrical parameter of the converter so as to modify the current of the electrical network, the sensor measures a resultant modified current, and the controller processes the measured resultant modified current to characterize the electrical parameter.

Abstract: A voltage source converter having first and second DC terminals for connection to a DC network is provided. The voltage source converter includes at least one converter limb that extends between the first and second DC terminals and first and second limb portions that are separated by a respective AC terminal for connection to a corresponding phase of an AC network. Each limb portion includes a chain-link converter which is defined by a plurality of series-connected switching modules which operate in combination to provide a stepped variable voltage source. The voltage source converter includes a control apparatus configured to coordinate operation of the chain-link converters to cause an exchange of power between the DC and AC networks, evaluate the performance of one of the pluralities of series-connected switching modules, and modify the operation of the respective chain-link converter when the performance becomes degraded to a predetermined amount.

Abstract: 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 ea

Abstract: In the field of high voltage direct current (HVDC) transmission, a voltage source converter comprises first and second DC terminals that are for connection to a DC network. The voltage source converter also includes at least one converter limb. The or each converter limb extends between the first and second DC terminals and includes first and second limb portions that are separated by a respective AC terminal for connection to a corresponding phase of an AC network. Each first limb portion extends between the first DC terminal and a corresponding AC terminal, and each second limb portion extends between the second DC terminal and the corresponding AC terminal. Each limb portion includes a respective chain-link converter which is defined by a plurality of series-connected switching modules which are operable in combination to provide a stepped variable voltage source.