- Power control and voltage regulation
DG active power control is a very important capability, but the use of DG power control may be very limited. At present, power control is probably most widely used in the event of an accident and the system capacity is reduced to help the system return to normal operation and prevent the accident from expanding.
The distributed power supply connected to the grid through the voltage level of 10(6)kV~35kV should have active power regulation capability, the output power deviation and power change rate should not exceed the given value of the grid dispatching agency, and can be adjusted according to the grid frequency value, grid dispatching Signals such as agency commands regulate the active power output of the power supply.
The way that the distributed power source participates in the voltage regulation of the distribution network can include adjusting the reactive power of the power source, adjusting the input amount of the reactive power compensation equipment, and adjusting the transformation ratio of the power transformer.
The power factor at the grid-connected point should meet the following requirements:
① The synchronous generator type and converter type distributed power supply should have the ability to protect the power factor of the grid connection point within the range of 0.95 (leading) to 0.95 (lag);
② The asynchronous generator type distributed power supply should have the ability to ensure that the power factor at the grid connection point is adjustable in the range of 0.98 (leading) to 0.98 (lag).
The power factor and voltage regulation capability at the grid-connected point should meet the following requirements;
① The synchronous generator type distributed power supply should have the ability to ensure that the power factor of the grid connection point is continuously adjustable within the range of 0.95 (leading) to 0.95 (lag), and can participate in the voltage regulation of the grid connection point;
② The asynchronous generator type distributed power supply should have the ability to automatically adjust the power factor at the grid connection point within the range of 0.98 (leading) to 0.98 (lag). When there are special requirements, appropriate adjustments can be made to stabilize the voltage level;
③ The converter type distributed power supply should have the ability to ensure that the power factor of the grid connection point is continuously adjustable within the range of 0.98 (leading) to 0.98 (lag). When there are special requirements, appropriate adjustments can be made to stabilize the voltage level. Within its reactive power output range, it should have the ability to adjust reactive power output according to the voltage level of the grid connection point and participate in grid voltage regulation. Its adjustment method, reference voltage, voltage deviation rate and other parameters should be set by the grid dispatching agency.
- Start and stop
The start and stop of the distributed power supply will have a certain impact on the operation of the low-voltage power grid. The voltage and frequency of the operating power grid should be fully considered when the distributed power supply is started. When the power grid voltage and frequency are abnormal, the distributed power supply should not be started to prevent accidents. The distributed power supply connected to the grid through the 380kV voltage level can automatically monitor the grid conditions and start and stop, and can also be negotiated and determined by the power grid company according to local conditions; The instructions of the power grid dispatching agency must be implemented to ensure the safety of system operation and the personal safety of maintenance personnel.