Movable control power supply for power plant or intelligent transformer substation and control method thereof

Abstract

The invention provides a movable control power supply for a power plant or an intelligent transformer substation and a control method thereof, wherein the movable control power supply relates to the field of control technology for a power system. The control power supply comprises an AC input terminal, an AC switch, a monitoring module, a power supply module, an insulated monitoring device, an alarm device, a DC switch, a DC voltmeter, a DC ammeter, a current sensor, a voltage sensor and a DC output terminal. The monitoring module receives an instruction of an upper computer. A composite digital control mode in which fuzzy self-setting PI controlling and repeated controlling are combined is used for automatically adjusting input voltage. The control power supply outputs stable DC voltage. The insulated monitoring device automatically detects whether a DC output loop is grounded or insulation is complete. According to the movable control power supply, an integrated and modular structure is utilized; and functions such as digital intelligent monitoring, various protecting functions and insulation monitoring and alarming are performed; high convenience in field power supply inputting is realized; the dynamic performance of the power supply is effectively improved so that safe and stable operation of the power system with the movable control power supply is realized.

Description

technical field [0001] The invention relates to the technical field of power system control, in particular to a movable control power supply and a control method for a power plant or an intelligent substation. Background technique [0002] For newly built or expanded power plants and smart substations, in order to ensure their safe and stable operation, electrical secondary circuits and equipment (relay protection devices, safety automatic devices, control circuits, signal circuits) must be checked at the production site before they are put into operation in the power system , automatic regulation loop) integrity. The above-mentioned electrical secondary circuits and equipment all need a control power supply to drive, and the existing control power supply generally has two types. The first one uses the DC power supply of the power plant and substation as the control power supply. It is fixed in the house and has a metal frame cabinet structure. The main device is a battery ...

AI Technical Summary

Problems solved by technology

[0004] The problems of the first type of control power supply are as follows: ① The battery pack is composed of multiple batteries connected in series and in parallel, and is often in the "floating charging operation state". Due to the uneven charging and discharging voltage and current of each battery, it often causes battery plate shocks. Therefore, it is unreliable, and the workload of operation and maintenance is large; ②Each battery generates a lot of heat, the shell is a sealed structure, and there is no heat dissipation device on the body. If it cannot dissipate heat in time, there is a danger of explosion; in addition, each battery Due to heat, the plastic shell of the plastic shell will produce peculiar smell and cause pollution to the environment; ③ When testing secondary equipment such as "relay protection and automatic device equipment, switch operating mechanism, and main transformer tap adjustment equipment" on site, it is necessary to start from the power generation It is inconvenient to connect the test power supply to the DC system of the factory and substation, and the quality of the power supply voltage is unqualified due to the long lead cable and large voltage drop; The system bus voltage drops, causing the "monitoring, protection and automatic devices" to lose their working power, making the power system run without monitoring and protection, which will endanger the safe operation of the power system; ⑤ During the test of the secondary circuit equipment, if the AC Mistakenly connected to the DC test circuit, the AC volume will enter the DC system of the power plant and substation through the test circuit, which will cause the relay protection devices in other intervals to malfunction, causing large-scale power outages, and in severe cases, the power grid will be disconnected, affecting the safety and stability of the power system run

[0005] The problems of the second type of control power supply are as follows: ①The traditional transistor amplified DC power supply is used as the control power supply, the output voltage is manually adjusted, the output characteristics are poor, the DC ripple is large, the output voltage is greatly affected by the load, and the overcurrent capability is weak; The human-machine interface is poor, the protection function is simple, and there is no insulation monitoring and remote communication function; the power supply has low efficiency and heavy weight, which is not suitable for on-site work; The rectifier modules operate in parallel, and the feedback loop increases, which affects the stability of the DC system; ③The impact load capacity is poor; during the transmission test of the high-voltage circuit breaker and the relay protection device of the power plant and the smart substation, due to the high-voltage circuit breaker The fast opening and closing speed (millisecond level) is an impact load, and the output voltage of the power supply fluctuates greatly, which affects the accuracy of the transmission test of the high-voltage circuit breaker and the relay protection device; ④The adjustment range of the output DC voltage of the control power supply is narrow, which cannot meet DC voltage (85-110) U N When changing, the test voltage requirements for the secondary circuit equipment of the power system; ⑤The control power supply generally does not have the DC insulation monitoring function; The insulation monitoring circuit is insensitive, or the alarm is rejected; ⑥The controller of the power supply adopts repetitive control-digital control mode, but the dynamic response is slow; although the repetitive control can ensure that the output waveform of the power supply is accurately tracked to the given value, the result obtained by repeated control The control command is not output immediately, but is output after a delay of one reference cycle; if there is interference inside the control power supply, it will take at least one reference cycle to eliminate the influence of the interference on the output. produce any regulation effect that seriously affects the dynamic performance of the control power supply

Images