The auxiliary part control part of the control part is mainly composed of a PLC, an open relay and an auxiliary power supply. Because we use GE 90-30 series PLC in the computer monitoring system of the power station, the PLC work is stable and reliable. Therefore, we also decided to use GE PLC in the auxiliary machine transformation, but the auxiliary system is relatively semaphore and The control amount is small. If the 90-30 series PLC is used, it is not only costly but also a waste of resources. Therefore, we chose the GEVersaMaxMicro series PLC with high cost performance.
According to the actual situation, we decided to use IC200UAL005CPU control module, which is 23 points IO, 13 point 24VDC switch input, 9 point relay switch output, 1 point 24VDC transistor output, 2 point 420mA analog input, 24VDC power supply powered by. For the speed control oil pressure control device and butterfly valve (ball valve) oil pressure control device input switch node is not enough, in addition to use IC200UEX012 as an expansion module, the module is 14 points IO, of which 8 points 24VDC switch input, 6 point Relay switch The output is also powered by a 24VDC power supply. The display panel uses the IC200DTX450 module to display local operating conditions. Although the screen is small, it is sufficient as a simple local display.
The pressure transmitter collects the relevant pressure and converts the pressure into a 420 mA current signal and sends it to the PLC. The PLC transmits the pressure signal to the monitoring system after the corresponding processing, and monitors the pressure signal. At the same time, the analog quantity collected is used as the backup quantity for control, that is, when the relevant pressure switch fails, the pressure signal collected by the pressure transmitter is controlled.
The pressure switch uses the H100-704 and 705 models of the US UE company. This type of pressure switch has the characteristics of accurate and stable operation. The original pressure measuring components of the Xiqiao River cascade power station are mostly Bourdon tube pressure switches and a small number of intelligent electronic pressure switches, but the Bourdon tube pressure switches are difficult to adjust and the operating points are variable. The intelligent electronic pressure switches are reset when there is power failure. And other issues. The pressure switch has the advantages of convenient setting, stable operating point and no need for external power supply, so it is most ideal as the main control signal of the pressure control system.
For the control of the water level of the collecting well, the water level collecting component has two sets of liquid level transmitter and liquid level switch. Considering the reliability of the control, the direct control quantity adopts the passive contact mode. Therefore, the water level control signal of the water level control system of the collecting well adopts the LFL3 type cable float level switch of Germany P+F. The switch uses a float switch connected to a flexible cable as a liquid level contact contact component. When the liquid level and the float rise above a certain angle, the switch will have an open (break) contact signal output, and the cable float liquid The material of the switch cable is made of special material, which is resistant to chemical corrosion and does not decompose toxic substances. It is suitable for water level control of water collection wells in hydropower stations.
The liquid level transmitter is an automatic component used to measure the water level of the collecting well. Previously we used the liquid level transmitter of Mike, but it was found that the drift was large after a long time of use. This time we selected the Swiss KELLER. The company's liquid level transmitter, through actual use, proves that the effect is better. At the same time, the water level of the collecting well collected by the liquid level transmitter is transmitted to the monitoring system through the auxiliary machine control system, so that the operating personnel can monitor the water level of the collecting well, and the analog quantity is used as the backup control quantity, when the collecting well liquid level switch The water level of the collecting well is temporarily controlled when the problem occurs.
Control cabinet design The control cabinet is part of the assembly control components and electrical components. Considering the rigidity and appearance of the cabinet, all control cabinets are made of 2mm steel plate, and the interior of the cabinet is designed to be variable in structure, ie U Type rails and cable ducts allow flexible assembly of components within the cabinet to meet specific needs. The control cabinet has a simple appearance and consists only of the power indicator light, the operation mode switch and the display panel, which not only satisfies all the functional requirements but also makes the whole cabinet beautiful and generous.
The software design software is mainly composed of three parts, one is PLC control and communication program, the other is the communication program of the host computer monitoring system, and the third is the related man-machine interface and text and voice alarm program. The PLC program is written in Versapro programming software and is programmed in ladder mode.
The communication program in the power station monitoring system is programmed by C language, which makes seamless connection with the original system. The man-machine interface and the text and voice alarm program are compiled by the power station monitoring system with its own software, so that the human-machine interface is friendly and the alarm is accurate and timely.
The function of the hydraulic control system of the unit governor and the hydraulic control system of the ball valve (1) The oil pressure is supplied to the governor (ball valve) due to the pressure oil tank, or the oil pressure is caused by oil leakage in the oil circuit system. When the lower limit of the working pressure is reduced, the working oil pump is started to supply oil to the pressure oil tank; when the oil pressure returns to the upper limit of the working oil pressure, the oil pump is stopped.
(2) If the oil pressure in the tank continues to decrease to the lower limit of the working oil pressure due to the failure of the normal working oil pump or the continuous supply of oil due to the governor (ball valve), start the backup oil pump to supply the pressure oil tank. Oil, stop the reserve pump operation until the oil pressure returns to the upper limit of the working oil pressure.
Pumtip Micro Vacuum Pumps and compressors are based on a simple principal, the circular power from the motor is converted into oscillating movement by an eccentric, which moves up and down its central point, this motion is then transferred to a diaphragm by means of a connecting rod, an elastic diaphragm, which in conjunction with an inlet and outlet valve creates a pumping action.
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