CN-116556468-B - Control method suitable for water supply system pressure relief device with back pressure technology

Abstract

The invention relates to a control method suitable for a pressure relief device of a water supply system with a back pressure technology, which is characterized in that a first pressure switch is defined to be P1, a second pressure switch is defined to be P2, when the switching value provided by the first pressure switch and the analog value provided by a pressure transmitter reach the operating pressure P1+ (P2-P1) x 95%, an electric flow control valve is kept for 30 seconds, if the pressure of the pressure transmitter is still higher than the operating value at the moment, a control cabinet controls the electric flow control valve to execute a valve opening program, when the pressure of the pressure transmitter is reduced to P1+ (P2-P1) x 20%, the control cabinet controls the electric flow control valve to stop opening, and when the electric flow control valve is fully opened, and the system pressure still cannot reach the value of P1+ (P2-P1) x 95%. The invention improves the stability and reliability of the technical water supply system of the hydropower station unit, and avoids the accident shutdown caused by the damage of the air cooler, the three bearing oil coolers, the water chilling unit, the main transformer and the air conditioner due to the overhigh pressure of each technical water supply system of the hydropower station.

Inventors

• YE SHIZHONG
• CHENG JIEMING
• Liao Xiangbo
• DUAN WEI
• LUO QIANLIN
• HE BAOMIN
• LI ZHIHUI

Assignees

• 中国长江电力股份有限公司

Dates

Publication Date

20260505

Application Date

20220901

Claims (3)

1. 1. The control method suitable for the pressure relief device of the water supply system with the back pressure technology comprises a water supply pipe connected between a water intake of a volute and a draft tube, wherein an electric flow control valve is installed on the water supply pipe and is electrically connected with a control cabinet, a pressure transmitter is installed on a pipeline between the electric flow control valve and the water intake of the volute and is used for being compared with a first pressure switch and a second pressure switch to avoid error measurement of the first pressure switch or the second pressure switch and cause misoperation of the electric flow control valve, the first pressure switch and the second pressure switch are installed on the pipeline between the pressure transmitter and the water intake of the volute and are used for controlling opening of the electric flow valve, the second pressure switch is used for controlling closing of the electric flow valve, the first pressure switch, the second pressure switch and the pressure transmitter are electrically connected with the control cabinet, a set pressure value of the first pressure switch is defined as P1, and a set pressure value of the second pressure switch is defined as P2, and the control system is characterized in that: when the switching value provided by the first pressure switch and the analog value provided by the pressure transmitter reach the action pressure P1+ (P2-P1) multiplied by 95%, the electric flow regulating valve is kept for 30 seconds, and if the pressure of the pressure transmitter is still higher than the action value at the moment, the control cabinet controls the electric flow regulating valve to execute a valve opening program; In the valve opening process, when the pressure of the pressure transmitter is reduced to P1+ (P2-P1) multiplied by 20%, the control cabinet controls the electric flow regulating valve to stop opening; when the electric flow regulating valve is fully opened and the system pressure still cannot reach below P1+ (P2-P1) multiplied by 95%, the electric flow regulating valve is kept in a fully opened state.
2. 2. The control method for a water supply system pressure relief device with backpressure technology according to claim 1, wherein: When the pressure of the second pressure switch and the pressure transmitter is lower than P1+ (P2-P1) multiplied by 5%, the electric flow regulating valve is kept for 1 minute, and if the pressure is still lower than P1+ (P2-P1) multiplied by 5%, the control cabinet controls the electric flow regulating valve to be closed; and when the pressure of the second pressure switch and the pressure transmitter is reduced to P1+ (P2-P1) x 5%, continuing to execute the valve closing procedure, and repeating the valve closing procedure until the electric flow regulating valve is completely closed.
3. 3. The method for controlling the pressure relief device of the water supply system with the back pressure technology according to claim 2, wherein in the valve closing process, when the electric flow regulating valve is in a stop state for more than 10 minutes, the control cabinet exits the valve closing process and sends out an alarm signal for reminding maintenance personnel to adjust the water supply system.

Description

Control method suitable for water supply system pressure relief device with back pressure technology Technical Field The invention belongs to the technical field of operation and maintenance of hydroelectric generating sets, and relates to a control method suitable for a water supply system pressure relief device with a back pressure technology. Background A technical water supply system of a hydropower station adopts self-flow water supply, and volute water is supplied to cooling equipment such as three bearing oil coolers, air coolers and the like through a water filter, a two-stage pressure reducing valve and a four-way reversing valve. The four-way reversing valve changes direction, the pressure reducing valve fails, and the like, so that the system pressure is increased, the stable operation of the technical water supply system and the hydroelectric generating set is endangered, the pressure reducing valve is required to accurately and stably act at the moment, part of high-pressure water is discharged, the pressure of the water supply system is reduced, and the stable operation of the water supply system is ensured. After the secondary pressure reducing valve of the hydropower station is provided with the mechanical hydraulic pressure relief valve, partial water of the system can be discharged to tail water through the action of the mechanical hydraulic pressure relief valve, the pressure of the system is reduced, and the tail water level is higher than that of the pressure relief valve, so that the pressure after the pressure relief valve changes along with the tail water level. The analysis results in the above-mentioned situation because the mechanical hydraulic relief valve uses the hydraulic pilot valve to drain or replenish water from the main valve control chamber, thereby controlling the relief valve opening and closing. The control mode has two major disadvantages: firstly, back pressure is easy to change after the valve, so that the pressure relief valve is controlled to be opened and closed inaccurately, and even when the back pressure is large, the valve is difficult to open. And secondly, the opening degree cannot be timely adjusted according to the pressure before the valve is opened, so that the opening degree of the pressure relief valve and the current pressure are in an optimal state, and the system pressure is prevented from being too low or too high due to too large or too small opening degree. Disclosure of Invention In order to solve the problem that the background art provided, this patent aims at designing a control method suitable for take backpressure technique water supply system pressure relief device, solves relief valve uninstallation pressure inaccuracy, is not applicable to the operating mode that tail water level changed, the difficult problem of relief valve action. In order to achieve the above purpose, the technical scheme is that the pressure relief device suitable for the water supply system with the back pressure technology comprises a water supply pipe connected between a volute water intake and a draft tube, an electric flow regulating valve is arranged on the water supply pipe and is electrically connected with a control cabinet, a pressure transmitter is arranged on a pipeline between the electric flow regulating valve and the volute water intake, a first pressure switch and a second pressure switch are arranged on a pipeline between the pressure transmitter and the volute water intake, and the first pressure switch, the second pressure switch and the pressure transmitter are electrically connected with the control cabinet. Preferably, the first pressure switch is used for controlling the electric flow valve to be opened, and the second pressure switch is used for controlling the electric flow valve to be closed. Preferably, the pressure transmitter is used for comparing with the first pressure switch and the second pressure switch, so that the error of measurement of the first pressure switch or the second pressure switch is avoided, and the misoperation of the electric flow regulating valve is avoided. The invention also provides a control method suitable for the pressure relief device of the water supply system with the back pressure technology, which defines the set pressure value of the first pressure switch as P1 and the set pressure value of the second pressure switch as P2: when the switching value provided by the first pressure switch and the analog value provided by the pressure transmitter reach the action pressure P1+ (P2-P1) multiplied by 95%, the electric flow regulating valve is kept for 30 seconds, and if the pressure of the pressure transmitter is still higher than the action value at the moment, the control cabinet controls the electric flow regulating valve to execute a valve opening program; In the valve opening process, when the pressure of the pressure transmitter is reduced to P1+ (P2-P1) multiplied by 20%, the control cabinet controls