A curable silicone elastomer composition is disclosed. The composition comprises one or more non-fluorinated polydiorganosiloxane polymers and silica filler. The silica filler is at least partially treated with a fluorinated hydrophobing treating agent. Also provided is a method of making the composition and its use in the manufacture of insulators for high voltage applications, especially high voltage direct current (HVDC) applications and accessories such as cable joints, cable terminal applications, and connectors. The fluorinated hydrophobing treating agents are selected from one or more silanol terminated fluorinated siloxane oligomer(s) having from 2 to 20 siloxane units, and/or one or more fluorinated silane diol(s), and/or one or more fluorinated trialkoxy silane(s), and/or one or more fluorinated silazane(s), or a mixture thereof.

A grid-forming wind turbine control method for a diode rectifier unit-based offshore wind power transmission system. A control system for controlling a grid-side converter has a three-layered structure, where a first layer is a combination of an active power controller and a reactive power controller; a second layer is a voltage controller; and a third layer is a current controller. The actual reactive power is represented by a per-unit value of a capacity of a corresponding wind turbine unit. The wind turbine units have the same reactive-power reference value, which is constant and does not change with time. The reactive power controllers of all wind turbine units have the same structure and parameters.

A bipole power transmission scheme with two independent converts, two power feed and one return conduit. During operation of the bipole power transmission scheme under abnormal conditions, when a return conduit is faulty and unable to provide a return current path, each converter controller is programmed to monitor the first power feed in the first transmission conduit and the second power feed in the second transmission conduit and, if the first power feed in the first transmission conduit and the second power feed in the second transmission conduit differ from one another, at least one converter controller modifies the power infeed from its corresponding power source to reduce the difference between the first power feed and the second power feed.

The invention discloses an energy storage transient power coordinated control method for restraining subsequent commutation failures, which includes: detecting DC current, AC bus voltage and arc quenching angle on the inverter side; Controlling the energy storage power station to enter the transient control mode when the DC current is greater than the first current threshold or the AC bus voltage is less than the voltage threshold or the arc quenching angle is less than the first arc quenching angle threshold. By detecting the DC current and arc quenching angle on the inverter side, the active power output time instruction and reactive power output time instruction are determined respectively. The active power output amplitude instruction is determined by detecting the AC bus voltage, and the reactive power output amplitude instruction is determined by using the constraint of the total energy storage capacity.

A loss optimization control method for modular multilevel converters (MMCs) under fault-tolerant control is disclosed. The method includes the following steps: when a fault of a SM in a MMC occurs, bypassing the faulty SM to achieve fault-tolerant control; suppressing the fundamental circulating current using a fundamental circulating current controller; respectively calculating the loss of each SM in faulty arms and healthy arms by using loss expressions of different switching tubes in SMs of the MMC; aiming at the loss imbalance between the arms of the MMC, taking the loss of a healthy SM as the reference, adjusting the period of capacitor voltage sorting control in the faulty SMs, achieving the loss control over the working SMs in the faulty SMs, and finally achieving the loss balance of each SM in the faulty arms and the healthy arms. Compared with the conventional methods, the proposed method is easier to implement and does not increase the construction cost of MMCs.

A method of monitoring a split wind-turbine-converter system with at least one generator-side converter and at least one grid-side converter arranged at distant locations, and a DC-link in the form of an elongated conductor arrangement with at least one positive and at least one negative conductor. The impedance of the DC-link conductor arrangement is determined by means of DC-voltage sensors. The voltages between the positive and the negative conductors are determined at the generator-side converter and at the grid-side converter, and the difference between the voltages is determined. The impedance of the DC-link conductor arrangement is determined by putting the determined voltage difference in relation to the DC current flowing through the DC-link conductor arrangement. If the impedance exceeds a given impedance threshold a fault state is recognized.

A high voltage direct current (HVDC) transmission system is provided. The high voltage direct current (HVDC) transmission system includes: an integrated measurement panel; and an HVDC transmission device, wherein the HVDC transmission device is configured to: receive, from the integrated measurement panel, compensation values for compensating for the voltage values output through the first to Nth potential transformers, compensate for the voltage values output through the first to Nth potential transformers by using the received compensation values, and measure the actual voltage values by using the compensated voltage values.

A converter and an operation method thereof are provided. A converter interconnected with a wind power generation farm includes a power monitor unit configured to detect a direct-current voltage of an entire system interconnected with the converter, a control unit configured to compare the detected direct-current voltage of the entire system with a reference voltage and adjust an alternating-current voltage that is supplied to the wind power generation farm to a preset value, and a switching unit configured to perform a switching operation based on the adjusted preset value to convert alternating-current power into direct-current power.

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 source-network coordination type direct-current (DC) circuit breaker based on pre-charged capacitors for an MMC based DC grid is provided. The MMC based DC grid is provided with four converter stations, each having two converters, which are in loop connection through a double-loop DC overhead line. Two ends of each DC line connecting the converters are separately equipped with DC circuit breakers for isolating a fault of the DC line. An MMC active voltage adjusting control strategy is matched with pre-charged capacitor voltage in the self-adaptive mode to provide a beneficial breaking condition for a quick mechanical switch branch, so that the fault line is effectively cut off.