A converter scheme comprising a plurality of converters (32,34), the plurality of converters including at least one of • at least one set of parallel-connected converters (32,34); • a bipolar converter arrangement including a plurality of converters; • a multi-terminal converter arrangement including a plurality of converters, each converter (32,34) including a plurality of series-connected modules, each modules including switching elements controllable to operate each module to selectively provide a voltage source and to configure each converter to change between blocked and deblocked states, each converter (32,34) having a configurable output power level, the converter scheme further including a controller programmed to operate the converter scheme at a total power level which is distributed among one or more converters (32,34) configured in a deblocked state, characterized in that the controller is programmed to reconfigure the converter scheme from a first total power level to a second total power level by carrying out a first stage of decreasing an operating power of at least one converter (32,34) in a deblocked state from a first power level to an intermediate power level, at least one converter being in a blocked state, and then carry out a second stage of increasing the operating power of the or each deblocked converter (32,34) from the intermediate power level to a second power level, wherein the controller is further programmed such that: (i) when the first total power level is lower than the second total power level, the first stage includes a first mode so as to reconfigure at least one further converter (32,34) among the at least one converter being in a blocked state from a blocked state to a deblocked state and then increase an operating power of the or each further converter (32,34) to the intermediate power level so that the total power level is redistributed among the deblocked converters (32,34) at the intermediate power level; and (ii) when the first total power level is higher than the second total power level, the second stage includes a second mode so as to decrease the operating power of at least one selected of the deblocked converters (32,34) from the intermediate power level, at least one of the deblocked converter being not selected, and then reconfigure the or each selected converter (32,34) from a deblocked state to a blocked state so that the total power level is redistributed among the or each remaining deblocked converter (32,34) at the second power level. • at least one set of parallel-connected converters (32,34); • a bipolar converter arrangement including a plurality of converters; • a multi-terminal converter arrangement including a plurality of converters, (i) when the first total power level is lower than the second total power level, the first stage includes a first mode so as to reconfigure at least one further converter (32,34) among the at least one converter being in a blocked state from a blocked state to a deblocked state and then increase an operating power of the or each further converter (32,34) to the intermediate power level so that the total power level is redistributed among the deblocked converters (32,34) at the intermediate power level; and (ii) when the first total power level is higher than the second total power level, the second stage includes a second mode so as to decrease the operating power of at least one selected of the deblocked converters (32,34) from the intermediate power level, at least one of the deblocked converter being not selected, and then reconfigure the or each selected converter (32,34) from a deblocked state to a blocked state so that the total power level is redistributed among the or each remaining deblocked converter (32,34) at the second power level.