JP2002271996A - Synchronizing application device for synchronous generator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem of the necessity of making the frequency difference, phase difference, and voltage difference from those of power having been already supplied, below allowable ranges, and the problem of taking much time for this control until synchronizing application, when power is supplied to a place where commercial power is used, or an emergency synchronous generator has been already operated, using an emergency synchronous generator. SOLUTION: On the occasion of adding power supply by an emergency synchronous generator to commercial power, conditions stricter than synchronizing conditions are applied, and priority is given to not damaging a generator by troublesome synchronizing application. When the degree of emergency is high, such as when supply of commercial power is stopped, etc., by service interruption, etc., an allowance condition for synchronizing application of the emergency synchronous generator is eased up to a maximum allowance in a range of not damaging the generator, and priority is given to quickening the start of power supply to enable quick synchronizing application.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a synchronous input device for an emergency synchronous generator used in the event of a commercial power outage or the like, and more particularly, to a synchronous input device for emergency power supply in an emergency. The present invention relates to a synchronous input device.

[0002]

2. Description of the Related Art In many hospitals and large companies, a plurality of emergency synchronous generators are provided so that power can be supplied from the emergency synchronous generator in the event of a power outage or disaster. In addition, the emergency synchronous generator is used, for example, using only a small amount of electric power, and using only commercial power at night when the power rate is low, and supplementarily supplying power using the power generated by the emergency synchronous generator at the time of a general charge during the day. To keep contract power low,
Emergency synchronous generators were sometimes used for both disaster prevention and normal power supply.

[0003] However, there is no particular problem in supplying power in such an emergency synchronous generator when the emergency synchronous generator is operated alone to supply power. For example, as shown in FIG. The power supply 31 is supplied later by the emergency synchronous generator to the place where the electric power 30 is used, or the power supply by another emergency synchronous generator to the place where the electric power is already supplied from the emergency synchronous generator. In this case, the power supply 31 by the emergency synchronous generator has a phase difference, a frequency difference and a voltage difference like 32 between it and the commercial power 30. However, when power is supplied from the emergency synchronous generator by turning on the circuit breaker 33 while keeping the phase difference, frequency difference, and voltage difference as they are, excessive current flows through the generator, and if the generator is severely damaged, In addition to the above, a torque is applied to the generator in a direction in which the phase difference is adjusted to generate mechanical stress, and if this is repeated, the generator will be damaged. This has a particularly significant effect when power is supplied to the place where commercial power is supplied by the emergency synchronous generator later.

For this reason, conventionally, power is supplied from an emergency synchronous generator to a place where commercial power is supplied, or another emergency synchronous generator is placed where an emergency synchronous generator that is already operating is present. As shown in FIG. 4 and Japanese Patent Application Laid-Open No. 6-121462, power is supplied from a predetermined tolerance, such as a voltage difference of ± 1%, a frequency difference of ± 0.1 Hz, or a frequency difference of ± 0.1%. Control is performed so that the phase difference is within ± 7.5 °, and when these are achieved, the circuit breaker 33 is turned on by a signal from the AND circuit 43 and power supply is started.

The frequency difference and the voltage difference can be easily adjusted by adjusting the rotation speed of the motor driving the generator, but the phase difference can be adjusted by changing the rotation speed of the motor little by little. It is necessary to perform complicated control such as first adjusting the phase and then returning the rotational speed to the original frequency to adjust the frequency, which takes time. Particularly in an emergency synchronous generator in an urban area, a gas engine is often used as a motive power due to a problem of exhaust gas. However, it is difficult to control the speed of this gas engine, and it takes a long time to reduce the phase difference to an allowable value or less. As a result, multiple generators cannot be synchronized within the statutory time stipulated by the Fire Service Law, causing problems in places such as hospitals where power must be urgently supplied from an emergency synchronous generator during a power outage. There was something.

In order to solve the above problems, Japanese Patent Laid-Open No. 9-103 is disclosed.
In the publication No. 097, when power is supplied from a plurality of generators, excitation is not performed immediately after startup for a generator to be supplied later, and the generator is connected to a bus so that the generator is in the same state as the motor and the first generator is connected. There is disclosed an apparatus in which the phase difference is reduced in a short time and the time until the synchronization is turned on can be reduced by using the generator as a generator in a state where the phase is synchronously rotated and then the excitation is performed and the phase is synchronously rotated.

Japanese Patent Laid-Open Publication No. Hei 11-191996 has a voltage balance function for keeping a voltage deviation between two generators within a predetermined range, and a matching speed function for keeping a frequency deviation within a predetermined range. There is shown a system in which synchronous closing can be quickly performed by a synchronous closing function of closing a circuit breaker at a synchronization point where a deviation and a frequency deviation fall within a predetermined range.

[0008]

However, Japanese Patent Application Laid-Open Nos. 9-103097 and 11-19199 disclose these methods.
All of the devices disclosed in JP-A No. 6 are connected to the bus and then perform excitation, or control the engine speed at a high speed until the frequency difference becomes less than a certain value. It is composed of a complicated mechanism, such as having a device for fine adjustment of, and must be expensive.

In view of the above-mentioned circumstances, the present invention is applicable to a case where emergency power is high, such as when commercial power is stopped due to a power outage or the like, when power is supplied by an emergency synchronous generator to a location where commercial power is supplied. It is an object to provide an inexpensive device that can supply electric power more quickly.

[0010]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a system in which an emergency synchronous generator is used for both disaster prevention and normal power supply. In the case of additional power supply, priority should be given to applying stricter conditions for synchronous input and not causing damage to the generator due to complicated synchronous input. Tolerance conditions for the synchronous input of the synchronous generator for use have been relaxed to the maximum allowable range that does not damage the generator, and the synchronous input can be quickly performed by giving priority to the earlier start of power supply.

[0011] Thus, in the event of an emergency such as a power outage, a quick start of power supply can be realized, and in the case of addition to commercial power, a synchronous generator of a synchronous generator capable of starting power supply without damaging the generator. Can be provided at low cost, and a great effect can be brought about.

Therefore, in the present invention, as described in claim 1, commercial power and a plurality of synchronous generators are connected in parallel to the load, and auxiliary power supply to the commercial power by the synchronous generator and commercial power outage are performed. The synchronous input device of the synchronous generator in the system for performing power supply at the time, the synchronous input device has a plurality of synchronous input allowable conditions of the synchronous generator, and the synchronous input allowable condition in the auxiliary power supply to the commercial power; Feature different synchronization allowable conditions for power supply at the time

In this way, by making the synchronous generator allowable condition different between the case of using the auxiliary power supply for the commercial power and the case of using the power supply at the time of the commercial power failure, in the event of an emergency such as a commercial power failure, It is possible to set an allowable condition such that the start of power supply can be hastened, and it is not possible to quickly supply power in a place such as a hospital as described above, where power supply from the emergency synchronous generator at the time of a power failure must be urgently performed. Can be prevented.

According to a second aspect of the present invention, the plurality of synchronous input allowable conditions are such that the plurality of synchronous input allowable conditions are more supplementary to the commercial power than the synchronous input allowable condition in power supply at the time of a commercial power outage. It is characterized by the fact that the synchronous input allowable condition in power supply is strict.

That is, as described above, when the synchronous generator is synchronously turned on where commercial power is used, the phase difference has a greater effect on the generator than when the synchronous generator is turned on when commercial power is interrupted. In the case where the emergency synchronous generator is used when the power reaches the peak, there are times when the synchronization is performed several times a day. In such a case, a stricter synchronization requirement must be imposed. The generator may be damaged. On the other hand, in the event of a commercial power outage, the synchronous input is usually performed while the emergency synchronous generator of the same scale is operating, so even if the synchronous input allowable condition is somewhat relaxed, the damage is already operating It will be shared with the synchronous generator. Therefore, by slightly loosening the synchronous input allowable condition, early synchronous input becomes possible, and a great effect is brought about in a place such as a hospital where power must be urgently input from an emergency synchronous generator at the time of a power outage.

[0016] As described in claim 3, it is preferable that the plurality of synchronization enabling conditions are differences in phase difference.

[0017]

Embodiments of the present invention will be illustratively described in detail below with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention to them unless otherwise specified. This is just an example.

FIG. 1 is a schematic block diagram of an apparatus showing an embodiment of the present invention, and FIG. 2 is a detailed block diagram of a synchronization input control device 7 in FIG. In the figure, 1 is a commercial power supply,
2 _{1, 2 2,} ... are synchronous generator, 3 _{1, 3 2,} ... is a driving source such as an engine that drives a synchronous generator, 4 breaker commercial power supply 5 is a power failure detector of the commercial power supply , _{6 1, 6} 2,
... Are synchronous generator breakers, 7 ₁ , 7 ₂ ,... Are synchronous input control devices, 8 is a load, 11 is a generator output, 12 is a bus to the load, and 13 in FIG. And bus 1
A phase difference detection circuit 14 for detecting the phase difference between the two powers, and an output 14 of the phase difference detection circuit 13 and a plurality of allowable phase differences, for example, 1
A comparison circuit for comparing ± 7.5 ° as shown in FIG. 5 and ± 15 ° as shown in FIG. 16, and reference numerals 15 and 16 are allowable phase differences. This allowable phase difference is used properly. Reference numeral 17 denotes a voltage difference detection circuit that detects a voltage difference between the power of the generator output 11 and the power of the bus 12.
Is the voltage difference detection circuit output and the allowable voltage difference, for example, ± 1%
A comparison circuit 19 compares the generator output 11 and the bus 12
20 is a frequency difference detection circuit for detecting the frequency difference of the power of the power, and 20 is a frequency difference detection circuit output and an allowable frequency difference, for example, ± 0.1
A comparison circuit for comparing Hz, a synchronization control circuit 21 for controlling the rotation speed of the drive source 3 such as an engine to control the synchronization of the generator, and a reference numeral 22 for an AND circuit. Note that the allowable phase difference, allowable voltage difference, and allowable frequency difference in the drawing are merely examples, and it is obvious that the present invention is not limited to the values shown here. Although two allowable phase differences are shown in this example, the number can be increased according to the situation.

In the synchronous generator of the synchronous generator constructed as above, the commercial power circuit breaker 4 is normally turned on.
Therefore, power is supplied from the commercial power supply 1 to the load 8. When auxiliary power is supplied by the emergency synchronous generator from this state, first, the engine 3 drives the synchronous generator 2. Then, the power supply from the synchronous generator 2 and the power supply from the commercial power supply 1 to the load 8 correspond to the generator output 1 in FIG.
1. The signal is sent from the bus 12 to the phase difference detection circuit 13, voltage difference detection circuit 17, and frequency difference detection circuit 19 of the synchronization control device 7. Therefore, the phase difference detection circuit 13, voltage difference detection circuit 17, and frequency difference detection circuit 19 detect the phase difference, voltage difference, and frequency difference of the power from the generator output 11 and the bus 12, respectively, and compare circuits 14, 18, respectively. , Send to 20.

Since the power failure signal is not currently sent from the power failure detection circuit 5, the phase difference comparison circuit 14 has a strict tolerance 15 of a plurality of allowable phase differences 15, 16.
A comparison in which 7.5 ° is selected is performed, and if the generator output 11 of the synchronous generator 2 is not within this allowable phase difference, a signal is sent to the synchronous control circuit 21. This is a voltage difference comparison circuit 18,
The same applies to the frequency difference comparison circuit 19, in which the voltage difference is ± 1%.
If not, and if the frequency difference is not within ± 0.1 Hz, signals are sent to the synchronization control circuit 21 from the voltage difference comparison circuit 18 and the frequency difference comparison circuit 19, respectively. Therefore, the synchronization control circuit 21 controls the number of revolutions of the engine 3 that drives the synchronous generator 2, and controls the phase difference, the voltage difference, and the frequency difference to be within respective allowable ranges.

When the phase difference, the voltage difference, and the frequency difference fall within the predetermined allowable ranges, signals from the comparison circuits 14, 18, and 20 corresponding to the detection circuits within the allowable range are sent to the AND circuit 22. When signals from all the comparison circuits reach the AND circuit 22, the AND circuit 22
Sends a signal to open the gate and turn on the circuit breaker 6. Therefore, electric power from the synchronous generator 2 is supplied to the load 8.
Note that the same applies to the case where a plurality of synchronous generators 2 are operated, and the phase difference, voltage difference, and frequency difference between the output and the supplied power in each synchronous generator 2 fall within the predetermined allowable ranges. Each breaker 6 is ON
And power is supplied.

In this way, the auxiliary power supply to the commercial power is performed. If the commercial power supply 1 is interrupted, the power failure detector 5 first detects this and turns off the circuit breaker 4.
At F, a signal is sent to the synchronous input control device 7, and the synchronous input control device 7 starts driving the engine 3. Therefore, the circuit breaker 6 corresponding to the synchronous turning-on control circuit 7 of the synchronous generator 2 that has reached the rated power earliest is turned on, and power is supplied to the load 8.

[0023] Now, for example, 2 ₁ of the synchronous generator in FIG. 1 is the first and began feeding to the load 8, FIG. 2
Since power is transmitted from the synchronous generator 2 ₁ to the bus 12 in, second synchronization input control unit 7 ₂ of the synchronous generator ₂ is 2 _second output 11 ₂ and the load 8 side from the synchronous generator power to the phase difference between the synchronous generator 2 ₁ appearing on bus 12, the voltage difference, each of the detection circuit a frequency difference 13, 1
Detect at 7 and 19. Then, it is compared with the comparison circuits 14, 1
In Steps 8 and 20, comparison is made as to whether or not the power is within the respective allowable ranges. Since the power failure is currently occurring, a signal indicating that the power failure is present is sent from the power failure detector 5 to the phase difference comparison circuit 14. And the allowable phase difference is more gradual
± 15 ° is selected for comparison.

[0024] The comparator circuit 14, the generator output 11 ₂ of the synchronous generator 2 ₂ If not in this allowable phase difference ± 15 in ° sends a signal to the synchronization control circuit 21. The same applies to the voltage difference comparison circuit 18 and the frequency difference comparison circuit 19,
When the voltage difference is not within ± 1%, and when the frequency difference is ± 0.
If not within 1 Hz, a voltage difference comparison circuit 1
8. The signal is output from the frequency difference comparison circuit 19 to the synchronization control circuit 2
Sent to 1. Therefore, the synchronization control circuit 21 controls the number of revolutions of the engine 3 that drives the synchronous generator 2, and controls the phase difference, the voltage difference, and the frequency difference to be within allowable ranges.

When the phase difference, the voltage difference, and the frequency difference fall within the predetermined allowable ranges, signals from the comparison circuits 14, 18, and 20 corresponding to the detection circuits within the allowable range are sent to the AND circuit 22. When signals from all the comparison circuits reach the AND circuit 22, the AND circuit 22
Is opened and a signal to turn on the circuit breaker 6 is sent.
Therefore, electric power from the synchronous generator 2 is supplied to the load 8.

As described above, when it is necessary to start the power supply urgently due to a power failure or the like, the allowable phase difference is selected as 16 ± 15 ° which is gentler than when the power supply from the commercial power supply 1 is performed. A relatively time-consuming control of the phase difference can be performed in a short time, and the synchronization can be performed more quickly.
As a result, emergency synchronous generators using gas engines in urban areas can be synchronized in a short time, and power must be urgently supplied from emergency synchronous generators in the event of a power outage, such as in hospitals. It has a great effect in places.

As described above, the allowable phase difference in the figure,
It is obvious that the allowable voltage difference and the allowable frequency difference are merely examples, and are not limited to the values shown here. Although two allowable phase differences are shown in this example, it is possible to increase the number according to the situation.
A plurality of allowable voltage differences and allowable frequency differences may be provided and selected. Further, the example in which the plurality of allowable phase differences and the like are switched by the power failure detection device 5 has been described, but the switching may be arbitrarily performed by a similar control device.

[0028]

As described above, according to the first aspect of the present invention, the synchronous generator is synchronously turned on when it is used for auxiliary power supply of commercial power and when it is used for power supply during commercial power outage. By making the permissible conditions different, it is possible to set the permissible conditions such that the start of power supply can be hastened in an emergency such as a commercial power outage, and the power supply from the emergency synchronous generator at the time of the power outage, such as the hospital described above, can be provided. It is possible to prevent a problem that a power supply cannot be quickly performed in a place where the power supply must be performed urgently. In addition, since there are only a plurality of allowable synchronization input conditions and these are only used depending on the power supply situation, there is no need to use a complicated control circuit unlike the conventional device, and the configuration can be made inexpensively.

This synchronous input has a greater effect on the generator when the synchronous generator is synchronously input to a place where commercial power is used than when the synchronous generator is input when commercial power is interrupted. In the case where the emergency synchronous generator is used when the power reaches the peak, there are times when the synchronization is performed several times a day. In such a case, a stricter synchronization requirement must be imposed. The generator may be damaged. On the other hand, in the event of a commercial power outage, the synchronous input is usually performed while the emergency synchronous generator of the same size is operating, so even if the synchronous input allowable condition is somewhat relaxed, the damage is already operating It will be shared with the synchronous generator. Therefore, as described in the second aspect, the synchronous input can be performed earlier by making the synchronous input allowable condition in the power supply at the time of the commercial power failure somewhat looser than the synchronous input allowable condition in the auxiliary power supply to the commercial power, so that the hospital and the like can be used. This has a great effect where power must be urgently supplied from the emergency synchronous generator during a power outage.

[Brief description of the drawings]

FIG. 1 is a schematic block diagram of an apparatus showing an embodiment of the present invention.

FIG. 2 is a detailed block diagram of a synchronization input control device according to the present invention.

FIG. 3 is a diagram for explaining a phase difference when a synchronous generator is synchronously turned on.

FIG. 4 is a diagram for explaining a synchronization input condition.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Commercial power supply 2 Synchronous generator 3 Engine 4 Circuit breaker 5 Power failure detector 6 Circuit breaker for synchronous generator 7 Synchronization control device 8 Load 11 Generator output 12 Bus 13 Phase difference detection circuit 14 Comparison circuit 17 Voltage difference detection circuit 18 Comparison circuit 19 Frequency difference detection circuit 20 Comparison circuit 21 Synchronization control circuit 22 AND circuit

Claims (3)

[Claims] 1. Synchronous input of a synchronous generator in a system in which commercial power and a plurality of synchronous generators are connected in parallel to a load and auxiliary power is supplied to the commercial power by the synchronous generator and power is supplied during a commercial power outage. In the apparatus, the synchronous input device has a plurality of synchronous input allowable conditions of the synchronous generator, and the synchronous input allowable condition in the auxiliary power supply to the commercial power is different from the synchronous input allowable condition in the power supply during the commercial power outage. A synchronous input device for a synchronous generator. 2. The synchronous input allowable condition for auxiliary power supply to commercial power is set to be stricter than the synchronous input allowable condition for power supply during a commercial power outage. Synchronous generator of the synchronous generator described. 3. The synchronous input device of a synchronous generator according to claim 1, wherein said plurality of synchronous input allowable conditions are differences in phase difference.