JPS6138356B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an improvement in the operation control method of a tandem pumped storage power plant, and in particular, in the process of transitioning from pumping operation to phase adjustment operation under parallel conditions, the present invention accurately detects the phase adjustment mode. This invention relates to an operation control method that protects the main engine.

Generally, when shifting a pump-turbine from water pumping operation to phase adjustment operation, the guide vane 2 of the casing 1 is fully closed as shown in Fig. 1, and forced air is supplied through the air supply pipe 3 for pushing down the water surface. By this, the water around the runner 4 is pushed down below the runner, and the pushed down water level is detected by the water level detector 6 installed in the suction pipe 5, and after confirming that it is below a predetermined level, A method of switching to phase adjustment operation mode is adopted.

On the other hand, as shown in Figure 2, in the case of tandem water pumping equipment in which the water turbine 7 and the pump 8 are directly connected on one shaft, the input of the pump 8 is first changed to the water turbine in order to minimize power fluctuations in the system. After reducing the input to the system to zero, the pump water level is pushed down, and the resulting decrease in input is adjusted by the opening of the guide vane 9 on the water turbine 7 side, and the system shifts to phase adjustment mode. It is taken.

In this case, conventionally, the transition to the phase adjustment mode was made only on the condition that the water level of the suction pipe 10 of the pump 8 was below the set water level.
The following inconvenience occurred. That is, if the pump is still generating input even if the water level in the suction pipe falls below the set water level, the guide vane on the water turbine side is still open. Therefore, if a stop command is issued in this state, the sequence requires that the guide vane be fully closed for phase adjustment operation, so the guide vane will be stopped with it open, but in reality, the guide vane will remain open. It becomes impossible to shut down due to water flowing from the vanes.

In addition, when the water turbine side is in phase adjustment operation and the pump moves from pumping operation to phase adjustment operation by itself,
Since the guide vanes on the water turbine side are completely closed, there is no problem, but if the conventional pump operates in a phase-adjusted mode of operation by only detecting the suction pipe water level, the following problems occur. In other words, since the tandem water pump does not require a guide vane to adjust the water volume, the discharge valve 1 is used for water flow and disconnection as shown in Figure 2.
It is common to provide only 1, but in this case,
Even if the water level of the pump suction pipe 10 is below the set water level, the outer peripheral side of the runner 12 and the casing 13 are still filled with water, and a considerable pump input is generated. By opening the bypass valve 14 provided in the casing, this pump input is gradually reduced as the water is sequentially discharged to the suction pipe side, but if a stop command is entered during this process, the phase adjustment operation mode is activated. Since the main power supply is shut down, the main power supply disconnector is activated immediately, and the pump input is cut off, causing a large power fluctuation in the power grid.

The present invention has been made in order to eliminate the above-mentioned disadvantages of the conventional system, and the mode detection at the time of switching to the phase-mixing operation mode is performed by detecting the water level in the pump suction pipe, as well as by detecting the input of the generator motor and by detecting the guide vane. The object of the present invention is to provide an operation control method that makes a comprehensive judgment based on the result of opening degree detection, and enables safe and reliable transition from pumping operation to phase adjustment operation.

The details of the present invention will be explained below with reference to FIGS. 2 to 4.

When shifting from pumping operation to phase-mixing operation in the parallel state, the water turbine 7 is in the phase-mixing operation state, and when shifting to the pump 8 alone, the water turbine 7 is maintained in the same state. Further, when the water turbine loads the pump input and the input to the system becomes zero, the guide vane 9 is opened and the water turbine output corresponding to the pump input is generated.

Next, the discharge valve 11 of the pump 8 is fully opened to meet the pump cut-off condition, and the air supply valve 15 is immediately opened to lower the pump water level. As a result, the water level detector 1 installed in the pump absorbs water
6, when it is detected that the water level has fallen below the set water level, the air supply valve 15 is closed. This state is the so-called water surface pressing operation condition, and the vertical movement of the water surface of the suction pipe 10 of the pump 8 is automatically controlled by opening and closing the air supply valve 15.

Thereafter, the bypass valve 14 of the pump casing 13 is opened, the water in the pump impeller 12 and the casing 13 is discharged to the suction pipe 10 side, and the pump input is reduced.

In the above, confirmation that the guide vane 9 on the water turbine side is fully closed is performed by a guide vane open/close detector (not shown) connected to its operating shaft, and also when the input of the generator motor falls below a set value. This is confirmed by the power detection relay 20 shown in FIG. In addition, in Figure 3, 21 is the main shaft disconnector, 22
is the main transformer, 23 is the generator motor, 7 is a water turbine directly connected to this, and 8 is a pump connected in tandem to the water turbine. The detection relay 20 is activated when the shaft input P of the generator motor 23 becomes smaller than the set value Po. Then, the relay contact 20a is closed.

As shown in FIG. 4, this relay contact 20a is
A power line m, connected in series with the contact 16a of the water level detection relay, the contact 24a of the guide vane opening/closing detector of the water turbine, and the auxiliary relay 25 that operates when all of these contacts 20a, 16b, and 24b are closed.
connected between n. Contact 2 of auxiliary relay 25
5a is connected in series with a contact 26a of an auxiliary relay that detects a transition command from pumping operation to phase adjustment operation in the power supply circuit of phase adjustment operation detection relay 27.

Therefore, the phase-adjustment operation detection relay 27 confirmed that the shaft input of the generator motor was below the set value, the water level of the pump suction pipe was below the set water level, and the guide vane of the water turbine was fully closed. In this case, the relay will operate based on a command to transition to phase-mixing operation, and the transition to phase-mixing operation mode will be performed by operating the relay contacts (not shown).

As described above, in the present invention, the transition to the phase adjustment mode is performed on condition that the shaft input of the generator motor, the water level of the pump suction pipe, and the opening degree of the water turbine guide vane are below specified values.
The main engine is protected and the transition from phase-adjusted operation to stoppage can be carried out without any problems. In addition, when changing from pumping operation to water turbine operation, various mode changes can be carried out rationally, such as by detecting the water level in the pump suction pipe and switching to the water turbine operation mode in a short period of time as soon as the water surface is completely lowered.

Furthermore, according to the method of the present invention, when the pumping mode is changed by starting the water turbine, the shaft input of the generator motor becomes zero at the moment when the water turbine output corresponding to the pump input is generated, so that the shaft input becomes the set value. The following conditions are automatically met. Further, when the pump moves from water pumping to phase adjustment mode by itself, the guide vanes of the water turbine are in a fully closed state, so the condition for fully closing the guide vanes is also automatically satisfied. Therefore, reliable control can be performed using the same method regardless of whether or not the water turbine is started.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of a pump-turbine showing conventional phase-mixing operation, Figure 2 is a cross-sectional view to explain the transition to phase-mixing operation of tandem pumping equipment, and Figure 3 is a tandem-type pumped storage power plant. FIG. 4 is a circuit diagram showing an embodiment of the control circuit used in the present invention. 7... Water turbine, 8... Pump, 9... Water turbine guide vane, 10... Pump suction pipe, 11... Pump discharge valve, 12... Pump impeller, 13...
Pump casing, 14... Casing bypass valve, 15... Air supply pipe, 16... Water level detector, 16
a... Water level detection relay contact, 20... Power detection relay, 20a... Power detection relay contact,
24a...Contact point of guide vane opening/closing detector, 25
...Auxiliary relay, 25a...Auxiliary relay contact, 2
6a...Auxiliary relay contact, 27...Relay for phase adjustment operation detection.

Claims (1)

[Claims] 1. In a tandem pumped storage power plant in which a water turbine and a pump are directly connected on one shaft, the operation mode is changed from pumping operation to phase adjustment operation while the generator motor is operating in parallel with the grid. , the phase-mixing operation mode is detected on the condition that the water level of the pump suction pipe is below the set water level, the shaft input of the generator motor is below the set value, and the water turbine guide vane is fully closed. A method for controlling the operation of a tandem pumped storage power plant. 2 Connect the contacts of the power detection relay that activates when the shaft input of the generator motor becomes smaller than the set value, the contacts of the water level detection relay of the pump suction pipe, and the contacts of the guide vane opening/closing detector of the water turbine in series with the auxiliary relay. The contacts of this auxiliary relay are connected in series to the power supply circuit of the relay for detecting phase-mixing operation, and the contacts of this auxiliary relay are connected in series to the power circuit of the relay for detecting phase-mixing operation. An operation control method for a tandem pumped storage power plant according to claim 1, wherein the phase adjustment operation mode is detected by: