High voltage line secondary circuit wiring diagram

It is a schematic block diagram of switching capacitors according to power factor, as shown in Figure 15-20. When the power factor of the grid lags behind, the phase detector sends
a signal to activate the input delay amplifier, and Kl sends an input signal to the step selector. KM puts in a group of capacitors. When the grid power factor
leads, the cut-off delay amplifier is activated. K2 sends a cut-off signal to the step selector to cut off a group of capacitors. This is
a method that is widely used at home and abroad. It switches capacitors according to changes in power factor of the power grid, so that the system power factor is often at the optimal value. The investment part of this method
has gradually changed from mechanical and electrical methods to electronic counting in recent years, using electronic logic components and developing towards contactless.
    Based on the above analysis. There are various control methods for automatic compensation devices. However, since this static compensation is to adjust the overall average power
factor of the system, in the factory power supply system, an easy-to-operate and low-cost automatic compensation device has more practical significance. According to the current operation
situation, the two most widely used ones are time-based and voltage-based.
    For example, the time-based adjustment system in the United States is about 45%. The voltage-adjusted system is 40%. The two together account for
more than 85" of the entire regulation system.
    The dispatch center of the power system
should adjust . This method is simple Reliable and highly economical, this method is also used to replace automatic adjustment in some centralized compensation devices of factory power supply systems that have realized movement
. For example, in the United States, about 10% of the compensation capacitors adjusted in this way account for The installed capacity is more than 40%
. For factories with a capacity close to 2000kvar, about 50% are controlled and dispatched by system control, and the larger capacity capacity compensation device (1000kvar)
even reaches 67.5%. At present, this method The development direction is to use electronic logic components and develop towards contactless.