JP3464346B2 - Thyristor switch off device in variable speed pumped storage power generation system - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thyristor when a secondary side of an AC excitation synchronous machine is short-circuited by a thyristor switch due to an accident occurring on the primary side of the AC excitation synchronous machine in a variable speed pumped storage hydropower system. The present invention relates to a switch off device.

[0002]

2. Description of the Related Art FIG. 11 is a circuit diagram of a thyristor switch OFF device in a conventional variable speed pumped storage system using a thyristor switch. In the figure, 1 is an AC excitation type synchronous machine, 2 is a main transformer, 3 is a circuit breaker connected to a system of a main transformer 2, 4 is an AC excitation type synchronous machine 1 and a main transformer 2.
A circuit breaker connected between the two is a secondary excitation device that supplies a variable frequency power source to the AC excitation synchronous machine 1, and a thyristor switch 6 that short-circuits the secondary side of the AC excitation synchronous machine 1.

Next, the operation will be described. When an accident occurs on the primary side of the AC excitation synchronous machine 1, a thyristor switch 6 is provided to protect the secondary excitation device 5 from overvoltage and overcurrent induced on the secondary side of the AC excitation synchronous machine 1 due to the accident.
Is turned on to short-circuit the secondary side of the AC excitation type synchronous machine 1. In this case, the turned-on thyristor switch 6 could not be turned off until the short-circuit current became zero.

[0004]

Since the conventional thyristor switch OFF device is constructed as described above, when the thyristor switch 6 is turned on, after the accident is removed, the secondary side of the AC excitation type synchronous machine 1 is removed. Since the series current flows, the current flowing through the thyristor switch 6 has a waveform as shown in FIG. 12, and the circuit breakers at both ends of the accident are opened at time T ₂ to eliminate the overcurrent and overvoltage. Even if the gate signal was turned off in an attempt to turn off, the current continued to flow for a long time before the current became zero, and during that time the thyristor switch 6 could not be turned off. Therefore, once the thyristor switch 6 is turned on, once the AC excitation synchronous machine 1
There was a problem that I had to stop.

The present invention has been made to solve the above problems, and after the accident is eliminated, the thyristor switch is turned off in a short time so that the generator can be continuously operated without stopping the generator even in the event of a system accident. Therefore, it is an object of the present invention to obtain an off device of a thyristor switch in a variable speed pumped storage hydropower system that contributes to system stability.

[0006]

A device for turning off a thyristor switch in a variable speed pumped storage hydropower system according to claim 1 is a secondary excitation device for supplying a variable frequency to a secondary side of an AC excitation type synchronous machine. 1 of the AC excitation type synchronous machine
If a ground fault or short circuit occurs on the secondary side, a thyristor switch that short-circuits the secondary side of this AC excitation synchronous machine,
The thyristor switch is provided with a current supply command means for supplying a high-frequency current to the thyristor switch by superimposing the short-circuit current from the secondary excitation device via a reactor connected in series.

The off-device of the thyristor switch in the variable speed pumped storage hydropower system according to the second aspect of the invention is a secondary excitation device that supplies a variable frequency to the secondary side of an AC excitation type synchronous machine, and the AC excitation type synchronization. When a ground fault or a short-circuit accident occurs on the primary side of the machine, the secondary excitation is performed via a thyristor switch that short-circuits the secondary side of the AC excitation synchronous machine and a reactor connected in series with the thyristor switch. The thyristor switch is provided with a current supply command means for supplying a current having a phase opposite to the short-circuit current from the device.

The off-device of the thyristor switch in the variable speed pumped storage hydropower system according to the third aspect of the present invention is a secondary excitation device for supplying a variable frequency to the secondary side of an AC excitation type synchronous machine, and the AC excitation type synchronization. When a ground fault or short-circuit accident occurs on the primary side of the machine, the thyristor switch that short-circuits the secondary side of the AC excitation type synchronous machine, and the resonance action of the reactor and the capacitor charged in advance cause the thyristor switch. And a resonance circuit that allows a current having a phase opposite to that of the short-circuit current to flow.

The off device of the thyristor switch in the variable speed pumped storage hydropower system according to claim 4 is a secondary excitation device that supplies a variable frequency to the secondary side of an AC excitation type synchronous machine, and the AC excitation type synchronization. If a ground fault or a short circuit occurs on the primary side of the machine, the thyristor switch that short-circuits the secondary side of the AC excitation synchronous machine, the reactor connected in series with this thyristor switch, and this thyristor switch A resonance circuit that causes a current having a phase opposite to that of the short-circuit current to flow in the thyristor switch by the resonance action of the capacitor connected in series to another thyristor switch and the reactor.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below. Embodiment 1. 1 is a configuration diagram showing an off device of a thyristor switch in a variable speed pumped storage hydropower system according to Embodiment 1 of the present invention. In the figure, 1 is an AC excitation type synchronous machine, 2 is a main transformer, 3 is a circuit breaker connected to the system of the main transformer 2, 4 is connected between the AC excitation type synchronous machine 1 and the main transformer 2. A circuit breaker, 5 is a secondary excitation device that supplies a variable frequency power source to the AC excitation type synchronous machine 1, 6 is a thyristor switch that short-circuits the secondary side of the AC excitation type synchronous machine 1, and 7 is a series connection with the thyristor switch 6. Connected reactor, 15
Is an auxiliary transformer, 16 is an output voltage of the auxiliary transformer 15 taken through the transformer for instrument 17, detects system fault elimination based on this voltage change, and sends a system frequency generation command to the secondary excitation device 5. This is a system fault elimination detection device (current supply command means).

Next, the operation will be described. When an accident occurs on the primary side of the AC excitation synchronous machine 1, overvoltage and overcurrent are induced on the secondary side of the AC excitation synchronous machine 1. When this overvoltage or overcurrent exceeds the withstand value setting value of the secondary excitation device 5, the secondary excitation device 5 is stopped and the thyristor switch 6 is activated by a control signal from a thyristor control circuit (not shown).
Throw in.

After the accident is removed, the gate signal from the control circuit is turned off, the secondary excitation device 5 is activated by the system frequency generation command from the system accident removal detection device 16, and the alternating current corresponding to the system frequency is supplied to the thyristor switch 6. Then, the alternating current is flown and superposed on the short-circuit current flowing in the thyristor switch 6, as shown in FIG. As a result, the current flowing through the thyristor switch 6, which originally took a long time to gradually decrease to zero as shown by the chain double-dashed line, quickly becomes zero, and the thyristor switch 6
Can be turned off. In FIG. 2, T ₁ is the gate-on time of the thyristor switch 6, and T ₂ is the accident elimination time.

Embodiment 2. FIG. 3 is a configuration diagram showing an off device of a thyristor switch in a variable speed pumped storage hydropower system according to Embodiment 2 of the present invention. Reference numeral 18 is a current detector, 19 is a secondary current phase detector (current supply command means) which sends an anti-phase generation command to the secondary excitation device 5 based on the current detected by the current detector 18, and other constituent elements are FIG. 1
Since it is the same as that of the first embodiment shown in FIG.

Next, the operation will be described. In the first embodiment, the gate signal from the control circuit is turned off, and in response to the reverse phase generation command from the secondary current phase detector 19, the secondary exciter 5 turns off the thyristor switch 6, which corresponds to the system frequency. However, in the second embodiment, as shown in FIG. 4, a current having a phase opposite to that of the short-circuit current flows in the thyristor switch 6 and the current flowing in the thyristor switch 6 flows. Is quickly set to zero and the thyristor switch 6 is turned off. In addition,
In FIG. 4, T ₃ is the time to start supplying the alternating current from the secondary excitation device 5.

Embodiment 3. FIG. 5 is a configuration diagram showing an off device of a thyristor switch in a variable speed pumped storage hydropower system according to Embodiment 3 of the present invention. 8 is a reactor (resonance circuit), 9 is a capacitor (resonance circuit), 10 is a power supply for charging the capacitor 9, 11 is a switch for connecting the power supply 10 to the capacitor, 12 is a thyristor which is a resonance circuit formed by the reactor 8 and the capacitor 9. The other components are the same as those in the first embodiment shown in FIG. 1, and therefore, the same parts are designated by the same reference numerals to omit redundant description.

Next, the operation will be described. When an accident occurs on the primary side of the AC excitation synchronous machine 1, overvoltage and overcurrent are induced on the secondary side of the AC excitation synchronous machine 1. When this overvoltage or overcurrent exceeds the tolerance setting value of the secondary excitation device 5, the thyristor switch 6 is turned on by a control signal from a thyristor control circuit (not shown) to short-circuit the secondary side of the AC excitation type synchronous machine 1. To do.

After the accident is removed, the charged capacitor 9 and the reactor 8 are connected in series to the thyristor switch 6 by closing the switch 12 at time T ₄ shown in FIG. In this case, since the switch 11 is already opened after the charging of the capacitor 9 is completed, the charge charged in the capacitor 9 is discharged and resonates with the reactor 8, and the resonance current shown in FIG. 7 flows through the thyristor switch 6. . Due to this resonance current, a current having a phase opposite to the short-circuit current flows through the thyristor switch 6, the thyristor switch current becomes zero as shown in FIG. 8, and the thyristor switch 6 is quickly turned off.

Embodiment 4. 9 is a block diagram showing an off device of a thyristor switch in a variable speed pumped storage hydropower system according to Embodiment 4 of the present invention. 13 is a thyristor switch (resonance circuit), 14 is a capacitor (resonance circuit) connected in series with the thyristor switch 13, and the series circuit of the thyristor switch 13 and the capacitor 14 is a series circuit of the thyristor switch 6 and the reactor 7. It is connected in parallel. Since the other components are the same as those of the first embodiment shown in FIG. 1, the same parts are designated by the same reference numerals and the duplicate description thereof will be omitted.

Next, the operation will be described. When an accident occurs on the primary side of the AC excitation synchronous machine 1, overvoltage and overcurrent are induced on the secondary side of the AC excitation synchronous machine 1. When this overvoltage or overcurrent exceeds the tolerance setting value of the secondary excitation device 5, the secondary excitation device 5 is stopped and the thyristor switch 6 and the thyristor switch 13 are turned on by a control signal from a thyristor control circuit (not shown). . Then, the thyristor switch 13 charges the capacitor 14 for 10 ms.
It turns on for about ec, and then turns off.

After the accident is removed, the thyristor switch 13 is turned on again to discharge the electric charge charged in the capacitor 14 through the reactor 7 and the thyristor switches 6 and 13,
Resonance occurs between the reactor 7 and the capacitor 14,
Due to this resonance action, a current having a reverse phase of the short-circuit current is passed through the thyristor switch 6, and the thyristor switch 6 and the thyristor switch 13 are quickly turned off as shown in FIG.

[0021]

According to the invention described in claim 1, since the reactor is connected in series with the thyristor switch to short-circuit the secondary side of the AC excitation type synchronous machine, it is possible to short-circuit without the reactor. Can also suppress the short-circuit current. In addition, after the accident is eliminated, the secondary excitation device superimposes an alternating current equivalent to the system frequency on the short-circuit current and flows it to the thyristor switch. Therefore, the thyristor switch current can be quickly set to zero and the thyristor switch can be turned off. it can. As a result, re-excitation from the secondary excitation device can be performed in a short time, so that continuous operation can be performed without stopping the generator even in the event of a system fault, which has an effect of contributing to system stability.

According to the second aspect of the invention, the reactor is connected in series with the thyristor switch to short-circuit the secondary side of the AC excitation type synchronous machine, and the short-circuit current is suppressed as compared with the case where the reactor is short-circuited. After elimination of the accident, the thyristor switch is configured so that a current of opposite phase to the short-circuit current is superposed on the thyristor switch from the secondary exciter, and the thyristor switch current is quickly set to zero and the thyristor switch is turned off. Since the re-excitation from the secondary excitation device can be performed in a short time, continuous operation can be performed without stopping the generator even in the event of a system fault, which has an effect of contributing to system stability.

According to the third aspect of the invention, after the accident is removed, the reactor and the previously charged capacitor are connected in series to the thyristor switch, a discharge current is caused to flow from the capacitor, and the resonance action between the reactor and the capacitor causes Since the resonance current is superposed on the short-circuit current and passed through the thyristor switch, the thyristor switch current can be quickly set to zero and the thyristor switch can be turned off. As a result, re-excitation from the secondary excitation device can be performed in a short time, so that continuous operation can be performed without stopping the generator even in the event of a system fault, which has an effect of contributing to system stability.

According to the invention described in claim 4, the thyristor switch connected to the reactor and the thyristor switch connected to the capacitor are turned on at the same time after the secondary excitation device is stopped, and the resonance action due to charging and discharging of the fault current of the capacitor is caused. Since it is configured to be used, the thyristor switch current can be quickly set to zero, the thyristor switch can be turned off, and re-excitation from the secondary excitation device can be performed in a short time. Continuous operation is possible without stopping, which has the effect of contributing to system stability.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an off device of a thyristor switch in a variable speed pumped storage hydropower system according to Embodiment 1 of the present invention.

FIG. 2 is a waveform diagram of thyristor switch current for explaining the operation of the first embodiment of the present invention.

FIG. 3 is a configuration diagram showing an off device of a thyristor switch in a variable speed pumped storage hydropower system according to Embodiment 2 of the present invention.

FIG. 4 is a waveform diagram of thyristor switch current for explaining the operation of the second embodiment of the present invention.

FIG. 5 is a configuration diagram showing an off device of a thyristor switch in a variable speed pumped storage hydropower system according to a third embodiment of the present invention.

FIG. 6 is a waveform diagram of thyristor switch current for explaining the operation of the third embodiment of the present invention.

FIG. 7 is a waveform diagram of a resonance current according to the third embodiment of the present invention.

[Fig. 8] Fig. 8 is an operation explanatory diagram of each part according to the third embodiment of the present invention.

FIG. 9 is a configuration diagram showing an off device of a thyristor switch in a variable speed pumped storage hydropower system according to Embodiment 4 of the present invention.

FIG. 10 is an operation explanatory diagram of each part according to the fourth embodiment of the present invention.

FIG. 11 is a configuration diagram showing an off device of a thyristor switch in a conventional variable speed pumped storage hydropower system.

FIG. 12 is a waveform diagram of thyristor switch current for explaining the operation of the conventional device.

[Explanation of symbols]

1 AC excitation type synchronous machine, 5 secondary excitation device, 6 thyristor switch, 7 reactor, 8 reactor (resonance circuit), 9 capacitor (resonance circuit), 13 thyristor switch (resonance circuit), 14 capacitor (resonance circuit), 16 System fault elimination detection device (current supply command means), 19 Secondary current phase detector (current supply command means).

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI H02P 9/00 H02P 9/00 B

Claims (4)

(57) [Claims] 1. A secondary excitation device for supplying a variable frequency to a secondary side of an AC excitation type synchronous machine, and one of the AC excitation type synchronous machine.
If a ground fault or short circuit occurs on the secondary side, a thyristor switch that short-circuits the secondary side of this AC excitation synchronous machine,
Of a thyristor switch in a variable speed pumped storage hydropower system comprising: current supply command means for causing a high-frequency current to flow through the thyristor switch from the secondary excitation device through a reactor connected in series with the thyristor switch. Off device. 2. A secondary excitation device for supplying a variable frequency to the secondary side of an AC excitation type synchronous machine, and one of the AC excitation type synchronous machine.
If a ground fault or short circuit occurs on the secondary side, a thyristor switch that short-circuits the secondary side of this AC excitation synchronous machine,
A thyristor switch in a variable speed pumped storage power generation system, comprising: current supply command means for causing a current having a phase opposite to a short circuit current to flow from the secondary excitation device to the thyristor switch through a reactor connected in series with the thyristor switch Off device. 3. A secondary excitation device for supplying a variable frequency to the secondary side of an AC excitation type synchronous machine, and one of the AC excitation type synchronous machine.
If a ground fault or short circuit occurs on the secondary side, a thyristor switch that short-circuits the secondary side of this AC excitation synchronous machine,
A device for turning off a thyristor switch in a variable speed pumped storage hydropower system, comprising: a resonance circuit that causes a current having a phase opposite to a short-circuit current to flow through the thyristor switch due to a resonance action of a reactor and a capacitor charged in advance. 4. A secondary excitation device for supplying a variable frequency to the secondary side of an AC excitation type synchronous machine, and one of the AC excitation type synchronous machine.
A thyristor switch for short-circuiting the secondary side of the AC excitation type synchronous machine when a ground fault or a short-circuit accident occurs on the secondary side,
The reactor connected in series with this thyristor switch, the capacitor connected in series with a thyristor switch other than this thyristor switch, and the reactor resonate with each other, and a current having a phase opposite to the short-circuit current flows through the thyristor switch. A thyristor switch off device in a variable speed pumped storage hydropower system including a resonance circuit.