JPH08126210A - Parallel off control device for commercial power supply linkage private generator - Google Patents

Abstract

PURPOSE: To ensure operation of an important load by separating a general load from a private generator to prevent its overload while operating parallel off the private generator from a commercial power supply by a signal detected by instantaneous interruption before interrupting the commercial power supply. CONSTITUTION: A parallel off control device 1 for a commercial power supply linkage private generator introduces power from special high voltage trunk lines 11, 12 lowers voltage transformers TR1 to TR3, and distributes power to high voltage distribution lines W1 to W3 of three systems. A general load L1 of lighting or the like is connected to the lines W1 to W3, to distribute private power from the lines W2, W3 to a high voltage bus W4 through distribution lines 13, 14. Breakers 52F24, 52F31 and 52F1T, 52R1S and a direction short-circuit relay DSR are connected in series to the distribution lines 13, 14. General loads L2 to L4, breakers 52FB1, 52FB2, 52FG, 52GB1 and 52FBS are connected to the high voltage bus 4. The private generator G, having a capacity of covering an important lad L5, is always operated. When the relay DSR is actuated, the breaker 52FB1 is interrupted. In this way, operation of the important load L5 is ensured to be continued.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an off-line control device for a private generator connected to a commercial power source, and particularly to a load such as a general lighting connected to a commercial power source via a bus bar, which causes little damage due to stop of power supply ( (Hereinafter referred to as “general load”) and a load such as a computer or an auxiliary device of a private generator that is damaged by power supply stop (hereinafter referred to as “important load”), it is important to have at least the capacity to operate the important load. The present invention relates to an off-line control device for a private generator for commercial power supply, which protects a private generator connected to a load-side bus bar from being overloaded when an instantaneous voltage drop of a commercial power supply occurs.

[0002]

2. Description of the Related Art When an instantaneous voltage drop or power failure occurs mainly due to an abnormality in a commercial power supply system caused by a lightning strike or the like, a voltage fluctuation model on the customer side generally causes a voltage fluctuation as shown in FIGS. It will be.

An instantaneous voltage drop (hereinafter abbreviated as "instantaneous voltage drop") means that when a failure occurs due to a lightning strike on a power transmission line or the like which constitutes a power system, the failure point is detected by a protective relay and the circuit breaker detects it. Until it is removed from the power system,
This is a phenomenon in which the voltage drops around a failure point. Further, the term "fault" used here means not only an accident in which electrical equipment is broken, but also a phenomenon in which a system abnormality such as a short-circuit fault due to a lightning strike or a ground fault occurs and an excessive current flows.

At the momentary voltage drop, for example, in the power feeding system as shown in FIG. 6, one line 6 of the two lines overhead power transmission lines 61 and 62 is used.
When the failure T as described above occurs in No. 2, the voltage drops in an extremely short time of 100 to 200 milliseconds until the failure T is removed, but the power failure does not occur. In this case, an instantaneous voltage drop as shown in FIG. 3 occurs on both the consumers A and B sides (FIG. 6).

In the power failure, for example, when the above-mentioned failure T occurs in the one-line overhead power transmission line 71 on the customer side B in the power feeding system as shown in FIG. 7, the customer B side is shown in FIG. Similarly, a power outage occurs, and at the same time, an instantaneous voltage drop occurs on the customer A side as shown in FIG. Customer B
On the side, power will be retransmitted after the system is switched or restored.

[0006] Therefore, when a normal commercial power source fails, such a voltage drop is often accompanied, and according to the report of the results survey (Electrical Joint Research, No. 46, Vol. 3), the power source drops in the heavy thunder area. Is less than 0.2 seconds 97%
It has been reported that 95% of cases fall within 60% of voltage drop, and it is reported that a complete blackout as shown in FIG. 5 rarely occurs.

As is apparent from FIGS. 3 to 5, the instantaneous voltage drop and the power failure appear as a common phenomenon of abnormal voltage drop at the start of their occurrence. Therefore, the effect of backup on private generators is also common at the start of its occurrence. When the voltage of the commercial power supply abnormally drops, the normal frequency does not change and only the voltage drops, so that a reactive current flows from the generator toward the failure point. The magnitude of this reactive current increases as the voltage drop decreases. In this case, the load (active current) of the generator does not increase due to the reactive current, and conversely, the load of the generator decreases due to the voltage decrease, and the circuit breaker 83 is connected to the commercial power source S as shown in FIG.
The problem does not occur even in the conventional power supply system 8 by the private power generator G that is interconnected via the. When an accident such as a short-circuit occurs in the secondary distribution line on the secondary side of the transformer 82 and a power failure as shown in FIG. 5 occurs, if the private generator G is overloaded with about four times the rated value, the coupling will be lost. It is configured to protect the generator G by breaking the shear pin.

[0008]

SUMMARY OF THE INVENTION Problems with the conventional power supply system 8 in which a commercial power source interconnection private generator is used as described above are as follows.
Due to the occurrence of the commercial power failure following the abnormal voltage drop, the relay 81 provided at the power-side power receiving point of the transformer 82 is cut off, and the generator G is operated independently, and at that moment, the commercial power source S is used until now. The loads 85 and 86 that were used are all generators G
Therefore, the generator G is overloaded. When the generator G becomes overloaded, the generator stops due to the breakage of the shear pin of the coupling that is coupled to the driving gas turbine or diesel engine, and the power supply is stopped, so that the generator auxiliary device and the computer are stopped. The operation of the important load 86 such as is stopped. As a result, computer data is deleted, supply of lubricating oil for the generator is stopped, and the backup function of the private generator G cannot be fully achieved.

The present invention has been devised in view of the above-mentioned problems of the prior art, and detects a power failure of a commercial power source in advance in a momentary diminished state before that, and commercializes a private generator by the detection signal. A solution for a private generator that is connected to a commercial power source that disconnects the general load from the private generator to prevent overload operation of the private generator so that important loads can be reliably fed by the private generator An object is to provide a column control device.

[0010]

In order to achieve the above-mentioned object, an off-line control device for a commercial power source interconnected private power generator of the present invention is a general load such as general lighting connected to a commercial power source via a bus. And an important load such as an auxiliary machine of a computer or a private generator, a private generator connected to the important load side bus bar and having a capacity for operating at least the important load, and a bus bar between the general load and the important load Is provided on a bus bar closer to the commercial power source than the general load, important load, and private generator, and the instantaneous disconnection of commercial power source is detected to trip the bus circuit breaker. And a protective relay that outputs a signal.

According to a second aspect of the present invention, the private generator can be a gas turbine generator.

As described in claim 3, the protective relay may be a directional short circuit relay (DSR).

As described in claim 4, the protection relay may be composed of an undervoltage relay (UVR).

According to a fifth aspect of the present invention, the protective relay includes a directional short circuit relay (DSR) and an undervoltage relay (UV).
R) and

[0015]

In the off-line control apparatus for the commercial power supply interconnected private electric generator of the present invention having the above-mentioned structure, the general load such as general lighting connected to the commercial power supply via the bus and the auxiliary equipment for the computer and the private electric generator. A busbar connection breaker is installed on the busbar with an important load such as a busbar connection.By opening and closing this busbar connection breaker, the general load and the important load can be separated or connected to each other to supply power from a commercial power source. It will be. The private generator that backs up the important load is connected to the bus line on the important load side.Therefore, it is installed on the bus line closer to the commercial power source than the general load, the important load and the private generator, and it detects the instantaneous voltage drop of the commercial power source. A protective relay that trips the busbar circuit breaker trips the busbar circuit breaker open when the commercial power supply drops momentarily, and even if the commercial power supply continues to the momentary power cut and the power is cut off, the general load is disconnected in advance for private use. It is possible to stably supply only important loads within its capacity without overloading the generator.

In the off-line control device for the private power generator connected to the commercial power supply according to the second aspect, since the gas turbine generator is used as the private power generator, the warm-up operation is unnecessary and the load fluctuation is prevented. The following capability is good, and a compact and large output can be obtained. Furthermore, a cogeneration system can be configured to supply steam and hot water.

According to another aspect of the present invention, there is provided a disconnection control device for a private generator for commercial power supply, wherein the protective relay is a directional short-circuit relay (D).
Since it is composed of SR), it responds with a relative phase angle with respect to a reference voltage or current, can detect the outflow of the reactive current from the generator to the commercial power source side, and can quickly control the busbar breaker.

According to another aspect of the present invention, in the disconnection control device for the private generator for commercial power supply connection, the protective relay is an undervoltage relay (U).
Since it is composed of VR), it does not operate with a slight voltage drop, but operates with a voltage equal to or lower than the set voltage to cut off the power supply in the bus bar, and reliability is enhanced.

In the disconnection control device of the private generator for commercial power supply connection according to claim 5, since the direction short circuit relay (DSR) and the undervoltage relay (UVR) are used together as the protective relay, the instantaneous interruption of the commercial power supply is caused. Both properties can be used for low.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following is a detailed description of the present invention with reference to the accompanying drawings according to its embodiments.

FIG. 1 is a system diagram of an off-line control device for a commercial power source interconnected private generator according to a first embodiment of the present invention, and FIG. 2 is a commercial power source interconnected private generator according to the second embodiment. FIG. 3 is an explanatory diagram of a commercial power supply sag, FIG. 4 is an explanatory diagram of commercial power sag-blackout, and FIG. 5 is an explanatory diagram of commercial power outage. .

In FIG. 1, the disconnection control device 1 of the commercial power supply interconnection private electric generator according to the first embodiment includes circuit breakers 52, respectively.
From a special high voltage mains line of a commercial power source via Line 1 and Line 2 12 equipped with R1 and 52R2, for example, 66 kV, 5
Power of 0Hz is introduced, and circuit breakers 52P and 52
15MVA transformers TR1, TR2, TR3 with S
Is distributed to three series of high voltage distribution lines W1, W2, W3. A general load L1 such as lighting is connected to each of the high-voltage distribution lines W1, W2, W3, and two series of low-voltage distribution lines W
On-premises power distribution is performed from 2, W3 to the high-voltage bus W4 via the two-line power distribution lines 13, 14.

Two breakers 5 are provided on each of the distribution lines 13 and 14.
2F24 / 52F31 and 52R1-T / 52R1-S and the direction short circuit relay DSR as a protective relay are arranged in series. The high-voltage bus W4 has a two-circuit distribution line 13,
A circuit breaker 52FBS between the fourteen, a general load L2, L3, L4 such as a general lighting and a circuit breaker 52FB-2 between the two general loads L2, L3 are arranged, and an auxiliary machine for a generator, a computer, etc. Power supply line W5 of the gas turbine generator G as a private generator that backs up the important load L5 of
In the part toward the connection point with, the generator disconnection busbar connection circuit breaker 52FB-1 and the two circuit breakers 52FG, 52GB-1
And are arranged. The gas turbine generator G has a capacity capable of covering the important load L5, is constantly operated under a load, and is in an operating state.

Bus disconnecting circuit breaker 52FB-1 for disconnecting the generator
Is controlled by the directional short-circuit relay DSR as a protective relay, and is opened by the connection disconnection trip signal at the time of a momentary voltage drop to interrupt the energization of the high-voltage bus W4, and the general load L1,
L2, L3, and L4 are power supply lines W5 of the gas turbine generator G
It is configured to be able to shut off from. Directional short circuit relay D
SR responds with a relative phase angle to the reference voltage or current,
It is possible to quickly respond to the busbar breaker 52FB-1. Therefore, when a failure occurs in the main line of the commercial power source due to a lightning strike or the like, and a voltage sag as shown in FIGS. 3 and 4 occurs in the distribution lines 13 and 14, the reactive current N from the gas turbine generator G toward the commercial power system. Flow, and the short circuit relay DS
R is the earliest to detect and disconnect the generator busbar breaker 52
FB-1 is opened and the bus bar communication is cut off. With this, even if a power failure follows the instantaneous voltage drop, it is possible to prevent the gas turbine generator G from being overloaded, and the power supply to the important load L5 is continued.

Although it is a very rare case with a recent commercial power source, a gas turbine generator is used when a power failure as shown in FIG. 5 occurs instantaneously or when an accident such as a short circuit occurs in the high voltage bus W4 on the premises. The cutting of the shear pin at the coupling portion of G prevents overload.

In the disconnection operation of the busbar breaker 52FB-1, normally, the time from the occurrence of a failure in FIG. 4 to the power outage (the time when the power company detects the failure and disconnects the breaker of the substation) It is said that it takes about 0.1 to 2 seconds, and the time required to disconnect the busbar breaker 52FB-1 is
A total of about 50 msec, which is the detection time of the directional short circuit relay DSR, about 50 msec, which is the disconnection operation time of the circuit breaker 52FB-1 and 20 msec which is the sequence operation time of the sequence operation auxiliary relay, is required to be about 120 msec. Therefore 0.2
When the abnormal voltage drop continues for more than a second, the gas turbine generator G can be operated only for the limited important load L5 due to the parallel disconnection of the high-voltage bus W4.

As shown in FIG. 2, the disconnection control device 2 for the commercial power supply interconnection private generator according to the second embodiment includes a circuit breaker 52.
Electric power is introduced to the distribution line W6 from the mains of the commercial power source through the lead-in line 21 provided with R, and a general load L6 such as lighting is connected to the distribution line W6 and a power supply line from the gas turbine generator G is supplied. W7 is a generator disconnection busbar connection breaker 5
2B, and an important load L7 such as a generator auxiliary machine or a computer is connected to the power supply line W7. The characteristic configuration of the second embodiment is that a direction short circuit relay DSR and an undervoltage relay UVR are connected as protection relays to the downstream side of the breaker 52R of the lead-in wire 21 together with CT and PT as shown in the figure. A directional short-circuit relay DSR that responds with a relative phase angle to the reference voltage or current, and an undervoltage relay UVR that does not operate at a slight voltage drop but operates at a set voltage or less, so that the instantaneous voltage on the commercial power supply side is faster and more reliable. The point is that the low level is detected and the busbar breaker 52B is opened.

By the way, in the disconnection control device 1 for the commercial power supply interconnection private generator according to the first embodiment, only the undervoltage relay UVR can be used as the protection relay instead of the direction short-circuit relay DSR.

[0029]

As is apparent from the above description, according to the off-line control device for the private power generator for commercial power supply of the present invention,
You can enjoy the following effects.

(1) A busbar connection breaker is provided on a busbar between a general load such as general lighting connected to a commercial power source through a busbar and an important load such as an auxiliary machine of a computer or a private generator. By opening / closing the busbar breaker under the control of a protective relay, the general load and the important load are separated from each other, or both are connected to be supplied with power from a commercial power source.

(2) The private generator for backup of the important load is connected to the important load side bus bar, and is provided on the bus bar closer to the commercial power source than the general load, the important load and the private generator, and is connected to the commercial power source. With a protective relay that trips the busbar breaker by detecting an instantaneous voltage drop,
When the commercial power supply drops momentarily, the bus bar connection breaker is tripped open, and even if the commercial power supply continues to go down and the power fails, the general load is disconnected in advance to prevent the private generator from becoming overloaded. It is possible to stably supply power only to important loads within the capacity.

(3) In the off-line control device for the private generator for commercial power supply connection according to claim 2, warm-up operation is unnecessary, followability to load fluctuation is good, and a compact and large output is obtained. be able to. Furthermore, by configuring a cogeneration system, it becomes possible to supply steam or hot water.

(4) In the off-line control device for the private generator for commercial power supply connection according to the third aspect, it responds with the relative phase angle with respect to the reference voltage and the current, and the busbar breaker can be quickly controlled.

(5) In the off-line control device for the private generator for commercial power supply according to claim 4, the power supply to the bus bar is cut off by operating at a set voltage or less, not by a slight voltage drop. This will increase reliability.

(6) In the disconnection control device for the private generator for commercial power supply connection according to claim 5, a direction short circuit relay (DSR) and an undervoltage relay (UVR) are provided as protection relays against a momentary voltage drop of the commercial power supply. Both characteristics of can be utilized.

[Brief description of drawings]

FIG. 1 is a system diagram showing an off-line control device for a commercial power source interconnection private power generator according to a first embodiment of the present invention.

FIG. 2 is a system diagram showing an off-line control apparatus for a commercial power source interconnection private power generator according to the second embodiment.

FIG. 3 is an explanatory diagram of an instantaneous voltage drop of a commercial power source.

FIG. 4 is an explanatory diagram of a commercial power source instantaneous voltage drop-blackout.

FIG. 5 is an explanatory diagram of a power failure of a commercial power source.

FIG. 6 is an explanatory diagram showing a first mode of occurrence of a voltage sag.

FIG. 7 is an explanatory diagram showing a second mode of occurrence of a voltage sag.

FIG. 8 is a system diagram of an off-line control device for a conventional commercial power supply interconnection private generator.

[Explanation of symbols]

 1.2 Disconnection control device for private power generator connected to commercial power supply 13.14 Bus line (distribution line) closer to commercial power supply 52FB-1 Bus line connection breaker DSR protection relay G Private power generator (gas turbine generator) L1 to L4 General load L5 Important load W4 Bus between general load and important load W5 Bus on important load side

Claims (5)

[Claims] 1. A general load such as general lighting connected to a commercial power supply via a bus and an important load such as an auxiliary machine of a computer or a private power generator, and at least the important load connected to the important load side bus. A private generator having a capacity to allow, a busbar connection breaker interposed on the busbar between the general load and the important load, and a busbar closer to the commercial power source than the general load, the important load and the private generator. A disconnection control device for a private generator for commercial power supply, comprising: a protective relay provided for detecting an instantaneous voltage drop of the commercial power supply and outputting a signal for tripping the busbar circuit breaker. 2. The disconnection control device for a commercial power source interconnected private power generator according to claim 1, wherein the private power generator is a gas turbine generator. 3. The protection relay is a directional shorting relay (D).
3. The disconnection control device for the private generator for commercial power supply according to claim 1, which is configured by SR). 4. An undervoltage relay (U)
A disconnection control device for a private generator for commercial power supply according to claim 1 or 2, which is configured by VR). 5. The direction short circuit relay (D)
SR) and an undervoltage relay (UVR), The parallel disconnection control apparatus of the private generator for commercial power supply of Claim 1 or 2 comprised.