JPH09149555A - Synchronizer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten the time required until a synchronous generator is turned on to the power system after the synchronization between the voltage of the power system and the voltage of the synchronous generator is taken. SOLUTION: This device closes the circuit of a synchronous generator to a power system by closing the circuit of a breaker which connects the synchronous generator with the power system, in case that all of voltage value difference between the voltage value of the voltage of the power system and the voltage value of the voltage of the synchronous generator, frequency difference, and phase difference are severally within the specified reference values. At this time, a making coil 13 is supplied with currents when the making coil 13 to close a breaker by current application, a contact switch 12, and a thyristor 18 are all turned on, and the contact switch 12 is turned on in case that the voltage difference value and the frequency difference are severally within the reference values, and the thyristor 18 is turned on in case that the voltage difference value, the frequency difference, and the phase difference are severally within the reference value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a synchronous charging device used when charging a synchronous generator to a power system.

[0002]

2. Description of the Related Art Recently, an increasing number of customers are supplying power to loads such as elevators and electric lights by using not only a power system from a power company but also a synchronous generator to generate private power. There is. When the synchronous generator is supplied to the power system, if the difference between the voltage value, the phase, and the frequency of the two voltages is larger than a predetermined range, the synchronous generator or the breaker may be damaged by a transient current at the time of the supply. There is a possibility that it will.
Therefore, in such a case, a synchronization input device that inputs the synchronous generator to the power system when the voltage generated by the synchronous generator is synchronized with the voltage of the power system is used.

[0003] A conventional synchronous input device will be described below.

FIG. 3 is a schematic diagram of an example of connection between a power system and a synchronous generator.

A load 2 is connected to the power system 1,
A load 4 is connected to the synchronous generator 3. Power system 1
And the synchronous generator 3 are connected via a circuit breaker 5,
The circuit breaker 5 in the open state is closed as necessary (hereinafter also referred to as “closing the circuit breaker”), and the electric power system 1 and the synchronous generator 3 are electrically connected.

The voltage V _G generated by the synchronous generator 3 controls the governor for adjusting the amount of fuel to the engine that rotates the synchronous generator 3 and the magnitude of the exciting current flowing through the exciting coil of the synchronous generator 3. Controlled by AVR, increasing the amount of fuel by the governor increases the frequency of the voltage V _G , and increasing the exciting current by AVR increases the voltage value. Such voltage control, the voltage V _G of the synchronous generator 3 occurs, for example, is to be equal to the voltage V _S of the electric power system 1 such as 50Hz with 6600 V.

However, as shown in FIG. 3, when the load 4 is connected to the synchronous generator 3, the load 4 constantly fluctuates so that, for example, the elevator operates or stops. The voltage V _G generated by the synchronous generator 3 fluctuates under the influence of this. For this reason, the synchronous input device operates the voltage V _G generated by the synchronous generator 3.
By the above voltage control, the circuit breaker 5 is closed, that is, to the power system 1 of the synchronous generator 3 at the moment when the voltage V _S of the power system 1 and the voltage V _G of the synchronous generator 3 are synchronized. Input.

FIG. 4 is a schematic diagram of a conventional synchronizing input device.

[0009] The voltage detector 6 outputs to the control unit 7 detects the voltage V _G of the voltage V _S and the synchronous generator 3 of the electric power system 1. The control unit 7 performs the determination process described later with reference to FIGS. 5 and 6, and when the control unit 7 determines that the voltage V _S of the power system 1 and the voltage V _G of the synchronous generator 3 are synchronized, causes the sequencer 8 to operate. In response to this, a closing command is output.

In the sequencer 8 receiving the turn-on command, the contact switch 9 is closed, and a current flows through the auxiliary relay 10. When a current flows through the auxiliary relay 10, the contact switch 12 closes and the closing coil 13 is energized, so that a current flows. When a current flows through the closing coil 13, the circuit breaker 5 is closed,
The synchronous generator 3 is put into the power system 1. The contact switch 11 is a contact switch for preventing malfunction,
Before the circuit breaker 5 is closed, it is in the closed state, and when the circuit breaker 5 is closed by the current flowing through the closing coil 13, the circuit breaker 5 is opened.

The reason why the contact switch 12 is not directly closed by the closing command from the control unit 7 but via the contact switch 9 and the auxiliary relay 10 is that a relatively large current is required for closing the circuit breaker 5. However, since the closing command from the control unit 7 cannot be closed because the current is small, the contact switch amplification is performed through the contact switch 9 and the auxiliary relay 10.

FIG. 5 is a block diagram showing the judgment processing in the control unit 7 shown in FIG. 4, and FIG. 6 is a flowchart of the judgment processing in the control unit 7 shown in FIG.

[0013] First, when a request for introduction into the power system 1 of the synchronous generator 3 (F-1), the voltage value of the voltage V _S of the power system 1 received from the voltage detector 6 and the synchronous generator 3 It compares the voltage value of the voltage V _G of, determining whether the difference ΔV is either within the reference value (F-2). If not within the reference value,
If the voltage value of the voltage V _G of the synchronous generator 3 is high (F-3)
The instructed to reduce the excitation current by AVR (F-4), directed to increase the exciting current by AVR when a low voltage value of the voltage V _G of the synchronous generator 3 (F-3) (F-5).

Next, the power system 1 received from the voltage detector 6
Of comparing the frequency of the voltage V _G of the frequency and the synchronous generator 3 of the voltage V _S, it is determined whether the difference ΔF Do reference values (F-6). If not within the reference value, the synchronous generator 3
If the frequency of the voltage V _G higher (F-7) is instructed to reduce the fuel supply by the governor (F-8), if a low frequency of the voltage V _G of the synchronous generator 3 (F-7 ) Is instructed by the governor to supply more fuel (F
-9).

Then, the difference ΔV between the voltage value of the voltage V _S of the electric power system 1 received from the voltage detection unit 6 and the voltage value of the voltage V _G of the synchronous generator 3 of the electric power system 1 received from the pressure detection unit 6 The difference ΔF between the frequency of the voltage V _{S and} the frequency of the voltage V _G of the synchronous generator 3, the phase of the voltage V _S of the power system 1 received from the voltage detection unit 6 and the phase of the voltage V _G of the synchronous generator 3. It is determined whether all of the differences Δθ are within the reference value (F-1
0). If all of them are within the reference value, the control unit 7 outputs an input command to the sequencer 8.

[0016]

However, in the above-mentioned conventional synchronous closing device, the synchronous generator 3 is input to the electric power system 1 after the voltage of the electric power system 1 and the voltage of the synchronous generator 3 are synchronized. The time required to reach ΔT was as follows.

That is, the control unit 7 controls the voltage value difference Δ
It is determined whether all of V, the frequency difference ΔF and the phase difference Δθ are within the reference values. If they are within the reference values, it takes 50 msec to output the closing command, and the contact switch 9 is closed. It takes 50 msec, 20 msec for the contact switch 12 to be closed, and 35 msec for the circuit breaker 5 to be closed.
Was 155 msec.

If this happens, the voltage of the synchronous generator 3 may fluctuate during this 155 msec. Therefore, the reference values set for the voltage value difference ΔV, the frequency difference ΔF, and the phase difference Δθ are equivalent to this amount. The margin must be taken into consideration, and conventionally, for example, the reference value of the voltage value difference ΔV is ± 2% of the voltage value of the power system 1, and the reference value of the phase difference Δθ is ± 11 °. A reference value ΔF ₀ of the frequency difference ΔF is obtained from

[0019]

## EQU1 ## ΔF ₀ = Δθ ₀ / ΔT In Equation 1, Δθ ₀ is the reference value of the phase difference Δθ.

Here, the reference value Δθ ₀ of the phase difference Δθ is ± 1.
Since it is 1 ° and ΔT is 155 msec, according to equation 1, the reference value ΔF ₀ of the frequency difference ΔF is ± 0.2 Hz.

In particular, when the load 4 is connected to the synchronous generator 3 as shown in FIG. 3, the chances that the voltage of the synchronous generator 3 falls within this reference value will decrease, and the power system 1 Even if a request for turning on the synchronous generator 3 is made, the turning on may not be performed easily.

For example, specifically, if the load 4 connected to the synchronous generator 3 is 20 to 30% or less of the rated value and the fluctuation range of the load 4 is up to about 5%, the conventional synchronous closing device is also used. However, if the fluctuation range of the load 4 exceeds 5%, governor control of the synchronous generator 3 and hunting of the load change occur, and the frequency of the voltage V _G of the synchronous generator 3 greatly changes. In many cases, the frequency difference ΔF cannot be set within the reference value and synchronization cannot be performed.

The present invention has been made in view of the above points, and shortens the time required from when the voltage of the electric power system is synchronized with the voltage of the synchronous generator until the synchronous generator is turned on to the electric power system. It is an object of the present invention to provide a synchronized insertion device.

[0024]

In order to achieve the above object, the present invention provides a voltage value difference between a voltage value of a voltage of a power system and a voltage value of a voltage of a synchronous generator, and a frequency of a voltage of the power system. When all of the frequency difference between the frequency of the voltage of the synchronous generator and the phase of the voltage of the power system and the phase of the voltage of the synchronous generator are within a predetermined reference value, respectively, the synchronous generator and the In a synchronous closing device that closes the synchronous generator into the power system by turning on a breaker that connects to a power system, a closing coil that closes the breaker by energizing, a contact switch, and a semiconductor switch. The energizing means for energizing the closing coil when both are turned on, and the contact switch is turned on when the voltage value difference and the frequency difference are within the reference values, respectively.
And a closing means for turning on the semiconductor switch when the voltage value difference, the frequency difference, and the phase difference are each within the reference value.

Further, the inputting means turns on the semiconductor switch through a photocoupler.

Further, the charging means is composed of a dedicated IC, and the processing is speeded up.

The semiconductor switch is a thyristor switch.

A diode is connected in parallel with and opposite to the thyristor switch.

[0029]

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described below with reference to the drawings.

FIG. 1 is a schematic view of an embodiment of a synchronization insertion device according to the present invention, and the same components as those in FIG. 4 are designated by the same reference numerals.

The voltage detector 6 detects the voltage V _S of the electric power system 1 and the voltage V _G of the synchronous generator 3 to detect the voltage V _{S of} the control unit 14.
Output to The control unit 14 performs a closing preparation process, which will be described later with reference to FIG. 2, and synchronizes the voltage value of the voltage V _S of the power system 1 with the voltage value of the voltage V _G of the synchronous generator 3, and the power system 1 of the power system 1. When it is determined that the frequency of the voltage V _{S and} the frequency of the voltage V _G of the synchronous generator 3 are synchronized, a closing preparation command is output to the sequencer 8. Further, the control unit 14 causes the power supply system 1
Of the voltage V _S , the voltage V _G of the synchronous generator 3, the frequency permission signal, and the voltage value permission signal.

The contact switch 9 is closed in the sequencer 8 which has received the closing preparation command, and a current flows through the auxiliary relay 10,
When a current flows through this auxiliary relay 10, a contact switch 12
Closes. In this state, the thyristor switch 18 is still
Is off, no current flows through the closing coil 13.

On the other hand, the closing judgment circuit 16 performs a closing judgment process which will be described later with reference to FIG.
Synchronizing the voltage value of _{S and} the voltage value of the voltage V _G of the synchronous generator 3, synchronizing the frequency of the voltage V _S of the power system 1 and the frequency of the voltage V _G of the synchronous generator 3, and the voltage of the power system 1. V _S
When it is determined that the phase of 1 is synchronized with the phase of the voltage V _G of the generator 3, a closing command is output to the photocoupler 17. The closing determination circuit 16 is, for example, a specially created I
It is configured by C, and the speed of the input determination process can be increased.

Upon receiving the closing command, the photocoupler 17 turns on the thyristor switch 18, and at this time, the contact switch 1
Since 2 is also closed, the closing coil 13 is energized and a current flows. When a current flows through the closing coil 13, the circuit breaker 5
Is input, and the synchronous generator 3 is input to the electric power system 1.

The photocoupler 17 is provided to prevent malfunction due to noise. The contact switch 11 is shown in FIG.
Similarly, the contact switch is for preventing malfunction, and is normally in a closed state, and is opened when a current flows through the closing coil 13 and the breaker 5 is closed. The diode 19 is connected in parallel with the thyristor switch 18 as shown in FIG. 1 in order to protect the thyristor switch 18 from surge voltage.

FIG. 2 is a block diagram showing the closing preparation processing in the control unit 14 and the closing judgment processing in the closing judgment circuit 16 shown in FIG.

First, the control unit 14 controls the synchronous generator 3
When there is a request to supply the electric power system 1 to the electric power system 1, the voltage value of the voltage V _S of the electric power system 1 received from the voltage detection unit 6 and the voltage value of the voltage V _G of the synchronous generator 3 are compared, and the difference is obtained. It is determined whether ΔV is within the reference value. If not within the reference value,
When the voltage value of the voltage V _G of the synchronous generator 3 is high, AVR
To instruct to decrease the exciting current, and to instruct to increase the exciting current by AVR when the voltage value of the voltage V _G of the synchronous generator 3 is low.

Next, the power system 1 received from the voltage detection unit 6
Comparing of the frequency of the voltage V _G of the frequency and the synchronous generator 3 of the voltage V _S, it is determined whether the difference ΔF Do reference values. When the voltage is not within the reference value, the voltage V _G of the synchronous generator 3
When the frequency is high, the governor is instructed to reduce the supplied fuel, and when the frequency of the voltage V _G of the synchronous generator 3 is low, the governor is instructed to increase the supplied fuel.

Then, the difference ΔV between the voltage value of the voltage V _S of the electric power system 1 received from the voltage detection unit 6 and the voltage value of the voltage V _G of the synchronous generator 3 of the electric power system 1 received from the pressure detection unit 6 If both the difference ΔF between the frequency of the voltage V _{S and} the frequency of the voltage V _G of the synchronous generator 3 is within the reference value, the control unit 14 outputs a closing preparation command to the sequencer 8.

The control unit 14 also includes a voltage detector 6
The voltage V _S of the electric power system 1 and the voltage V _G of the synchronous generator 3 received from the
If the difference ΔF between the frequency of the voltage V _S of the power system 1 and the frequency of the voltage V _G of the synchronous generator 3 received from the voltage detection unit 6 is within the reference value, a frequency permissible signal is output to the injection determination circuit 16. Then, the voltage V of the power system 1 received from the voltage detection unit 6
Difference Δ between the voltage value of _{S and} the voltage value of the voltage V _G of the synchronous generator 3
If V is within the reference value, the voltage value permission signal is output to the closing determination circuit 16.

In the closing judgment circuit 16, the difference Δθ between the phase of the voltage V _S of the power system 1 and the phase of the voltage V _G of the synchronous generator 3 is given.
Power system 1 considering whether the frequency allowable signal and the voltage allowable signal are present,
Difference ΔV between the voltage value of the voltage V _S of the synchronous generator 3 and the voltage value of the voltage V _G of the synchronous generator 3, the difference ΔF between the frequency of the voltage V _S of the power system 1 and the frequency of the voltage V _G of the synchronous generator 3, Difference Δθ between the phase of voltage V _S of grid 1 and the phase of voltage V _G of synchronous generator 3
When all of the above are within the reference value, the closing command is output to the photocoupler 17.

With this configuration, the contact switch 12 can be closed in advance when only the voltage value difference ΔV and the frequency difference ΔF are within the reference values, and the operation time of the thyristor switch 18 is several tens of μsec. Therefore, the circuit breaker 5 can be turned on as soon as the phase difference Δθ is finally within the reference value.

That is, in the synchronous closing device of the present embodiment, the time required from the time when the voltage of the electric power system 1 and the voltage of the synchronous generator 3 are synchronized to the time when the synchronous generator 3 is turned on to the electric power system 1. Indicates that the closing determination circuit 16 determines the voltage value difference ΔV,
It is determined whether or not all of the frequency difference ΔF and the phase difference Δθ are within the reference values. If they are within the reference values, it takes 25 msec to output the closing command and 35 msec to close the circuit breaker 5, It takes 60 msec in total.

Therefore, ΔT in equation 1 is 60 mse.
Therefore, according to Equation 1, the reference value ΔF _{0 of the} frequency difference ΔF
Can be ± 0.5 Hz. As a result, the load 4 of the synchronous generator 3 which has been impossible in the past is rated 20 to
Even if there is a load change of more than 5% at 30%, it is possible to make a synchronous input.

Further, since the time ΔT taken from the time when the voltage of the electric power system 1 and the voltage of the synchronous generator 3 are synchronized to the time when the synchronous generator 3 is turned on to the electric power system 1 is shortened, the frequency difference ΔF The reference value ΔF ₀ is ± 0.2 Hz as before.
If left as it is, the deviation of synchronization between the voltage of the electric power system 1 and the voltage of the synchronous generator 3 at the moment when the circuit breaker 5 is turned on can be smaller than in the conventional case. For this reason, there is an effect that the adverse effect of the transient current at the time of making on the synchronous generator 3 is reduced.

By the way, as described above, when the reference value ΔF ₀ of the frequency difference ΔF is ± 0.5 Hz, the synchronous generator 3
The circuit breaker 5 can be turned on even when the frequency of the voltage V _G is lower than the frequency of the voltage V _S of the power system 1 by 0.5 Hz. In this case, the synchronous generator is switched from the power system 1 at the moment when the circuit breaker 5 is turned on. There is a risk that power will flow into the power generator 3 and the reverse power relay installed to protect the synchronous generator 3 will malfunction. Therefore, if the circuit breaker 5 is closed only when the frequency difference ΔF is within the reference value ΔF ₀ and the frequency of the voltage V _G of the synchronous generator 3 is higher than the frequency of the voltage V _S of the power system 1. Electric power does not flow into the synchronous generator 3 at the time of synchronization input, and the reverse power relay may not malfunction.

Although the thyristor switch 18 is used in the present embodiment, the present invention is not limited to this, and a semiconductor switch such as a MOSFET switch or a GTO may be used.

[0048]

As described above, according to the present invention,
It is possible to provide a synchronous closing device that shortens the time taken from when the voltage of the electric power system is synchronized with the voltage of the synchronous generator until the synchronous generator is turned on to the electric power system.

[Brief description of the drawings]

FIG. 1 is a schematic view of an embodiment of a synchronization insertion device according to the present invention.

2 is a block diagram showing a closing preparation process in a control unit shown in FIG. 1 and a closing judgment process in a closing judgment circuit.

FIG. 3 is a schematic diagram of an example of connection between a power system and a synchronous generator.

FIG. 4 is a schematic diagram of a conventional synchronization input device.

5 is a block diagram showing a determination process in the control unit shown in FIG.

FIG. 6 is a flowchart of a determination process in the control unit shown in FIG.

[Explanation of symbols]

 1 Power System 2, 4 Load 3 Synchronous Generator 5 Circuit Breaker 6 Voltage Detector 7, 14 Control Unit 8 Sequencer 9, 11, 12 Contact Switch 10 Auxiliary Relay 13 Make-up Coil 16 Make-up Judgment Circuit 17 Photo-coupler 18 Thyristor Switch 19 Diode

Claims (5)

[Claims] 1. A voltage difference between a voltage value of a voltage of a power system and a voltage value of a voltage of a synchronous generator, a frequency difference between a frequency of a voltage of the power system and a frequency of a voltage of a synchronous generator, and a voltage of the power system. And all of the phase differences between the phase of the voltage of the synchronous generator and the phase of the voltage of the synchronous generator are each within a predetermined reference value, the synchronous power generation is performed by turning on a breaker that connects the synchronous generator and the power system. A closing coil for closing the circuit breaker by energizing, and energizing means for energizing the closing coil when both a contact switch and a semiconductor switch are turned on, Closing preparation means for turning on the contact switch when the voltage value difference and the frequency difference are within the reference values, respectively, the voltage value difference, the frequency difference and the phase difference Said semiconductor switch O when is within each of said reference values
A synchronous loading device, characterized by comprising: 2. The charging means turns on the semiconductor switch via a photocoupler.
The synchronous loading device described in. 3. The synchronous loading device according to claim 1, wherein the loading means is composed of a dedicated IC to speed up the processing. 4. The synchronous closing device according to claim 1, wherein the semiconductor switch is a thyristor switch. 5. The synchronous closing device according to claim 4, wherein a diode is connected in parallel with and opposite to the thyristor switch.