JP2002374625A - Cogeneration system provided with uninterruptible power supply function - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cogeneration system, equipped with an uninterruptible power supply function where in a distributed power supply system in linkage with a power system on the side of an electric power company, power can be supplied from a distributed power supply without interrupting power supply to load, even if power failure occurs in the power system, when the prime mover for the distributed power supply is at a stop. SOLUTION: The cogeneration system 5 is for a distributed power supply system 1, with which power is supplied to private load in linkage with the power system of an electric power company. In the cogeneration system, a power storage apparatus 35 is placed in the sub-output circuit 30 of a sub- generator 31G. If power failure is detected in the power system, when a main generator 21G is at a stop, power to the load is supplied from the power storage apparatus 35 and further control for starting the power generation of the main generator 21G is conducted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a distributed power supply that supplies power generated by a generator connected to an engine to an in-house load in synchronization with a power supply of a power supply system of a power company and operates in cooperation with the power supply system. The present invention relates to a cogeneration system (CGS) having an uninterruptible function in a system.

[0002]

2. Description of the Related Art In the past, power was purchased from a power company and consumed by supplying power to a private load (in-house load). As shown in FIG. 3, a generator 21G is driven by a prime mover 21E such as a diesel engine. A distributed power supply system 1X that drives and supplies power generated by the generator 21G to a private load in synchronization with a power supply of a power system of a power company has been used.

In this distributed power supply system 1X,
A power system (hereinafter referred to as a power system) for supplying power from a power company is connected to a generator-side circuit, and the power of the generator 21G is generated in synchronization with the power system. In this case, it is possible to provide a system link in which both powers 21 are continuously supplied to the own load without power interruption.

In this system link, if a power failure occurs on the power system side of the power company while the distributed power supply 21 is operating, a voltage drop on the power system side is detected by a current transformer or the like, and the Since the connection to the system is interrupted by the first circuit breaker 11 and the power supply to the private load is taken over by the distributed power supply 21, the private load can be continuously supplied with the power, so that no problem occurs.

[0005]

However, in this system link, the distributed power supply 21 controls the proportion of the power supply between the power system and the distributed power supply 21 in accordance with the fluctuation of the power used by the own load. Therefore, depending on the power used by the private load, there is a time when the power supply amount is sufficient only in the power system and the distributed power supply 21 stops operating.

If a power outage accident occurs in the power system on the side of the power company at the time when the distributed power supply 21 is stopped, the distributed power supply 2
Since the engine 21E on the first side is stopped and the second circuit breaker 22 is open, the power supply to the private load is stopped. Stopping the power supply to the private load causes a problem such as loss of stored data in a computer, a controller, or the like, occurrence of a control abnormality, and the like, which is a serious problem.

[0007] For this reason, devices that may cause a problem due to a power failure are individually provided with an uninterruptible power supply (UP).
S) Although a countermeasure of connecting 3 is conceivable, the implementation of this countermeasure requires a large investment and the power supply holding time of the uninterruptible power supply 3 is only several minutes. In the case where the device is present or unattended, there arises a problem that the normal stop of the device cannot be performed in time.

On the other hand, in this distributed power supply system, in order to make effective use of energy, electric power is obtained by a generator driven by a prime mover, and thermal energy of exhaust gas generated from the prime mover is used for hot water supply, cooling and heating, and the like. Many cogeneration systems are used.

In this cogeneration system, in addition to the main generator driven by the prime mover, a part of the heat energy of the exhaust gas discharged from the prime mover is recovered to form a sub-generator such as a turbine generator. And a co-generation system that has a sub-output circuit for a sub-generator in addition to the main output circuit of the main generator. is there.

In order to synchronize with the power of the main output circuit, the sub-output circuit first converts the power generated by the sub-generator into DC and then converts it into AC which is synchronized with the power of the main output circuit. A rectifier circuit and an inverter for this purpose are provided.

The present invention has been made to solve the above-mentioned problems of the prior art by utilizing the configuration of a cogeneration system, and an object of the present invention is to provide a distributed power supply linked to a power system on a power company side. In a system, even if a power failure occurs in the power system while the prime mover of the distributed power source is stopped, the power system is cut off and the power is continuously supplied from the distributed power source without interrupting the power supply to the private load. An object of the present invention is to provide a cogeneration system having an uninterruptible power supply function.

[0012]

A cogeneration system having an uninterruptible power supply function for achieving the above object is configured as follows.

1) The power of the main power generator driven by the engine and the power of the sub power generator that collects and generates the exhaust gas energy of the engine in synchronization with the power supply of the power system of the power company. A cogeneration system of a distributed power supply system for supplying a load, wherein the main power generator driven by the engine, the sub power generator for recovering energy of exhaust gas discharged from the engine to generate power, and A main output circuit of the main power generator connected in parallel to a power supply circuit of a system, a sub output circuit for outputting power of the sub power generator to the main output circuit or the power supply circuit, and the cogeneration. Control means for controlling the system, and a power storage device is provided in the sub output circuit, wherein the control means stops the main power generation device. When detecting that a power outage has occurred in the power system, supplying power to the private load using the power storage device as a power supply source and starting power generation of the main power generation device during the power supply. It is configured to perform.

This sub-generator is usually constituted by a generator having a rotor such as a turbine generator, but any device that recovers heat of exhaust gas and consequently converts thermal energy into electric energy. What is necessary is just another power generator.
Further, the power storage device can also be constituted by a battery or the like, but any device that can store and release electric energy can be used.

The occurrence of a power failure in the power system can be detected by a power state monitoring sensor such as a transformer installed in a power supply circuit of the power system.

According to this configuration, when it is detected that a power failure has occurred in the power system when the main power generator is stopped, power is supplied to the own load by the power storage device provided in the sub output circuit. Since the main power generator is started together with the power supply, interruption of the power to the private load can be avoided, and the power to the private load can be continuously supplied.

2) More specifically, in the cogeneration system having the uninterruptible function described above, a first breaker and a first switch are connected in series between the power system of the power supply circuit and the private load. Provided, the main output circuit having a second circuit breaker is connected in parallel to a first connection between the first switch of the power supply circuit and the private load,
The auxiliary output circuit is formed by serially providing a rectifier circuit, an inverter, and a transformer, and is connected to a second connection portion between the second breaker and the first junction of the main output circuit, and The power storage device formed of a second switch and a battery arranged in series is connected to the DC portion of the circuit, and the control unit controls the main power generation device, controls the inverter, and shuts off control by the first switch. The second switch is configured to perform charge control.

That is, the sub-generator generates electric power by the exhaust gas of the engine that drives the main generator, electrically recovers the heat energy of the exhaust gas, and uses the recovered electric power by the inverter to generate the electric power of the main generator. In a distributed power supply that regenerates in synchronization with a battery, a battery is installed at the DC input of the inverter, and upon detection of a power outage accident, the connection to the power system is cut off by operating the first switch, and the battery is disconnected. Operate the inverter as a power supply. Thus, power is continuously supplied to the private load so that the power supply is not interrupted.

At the same time, the engine is started, power generation is started by the main power generator, and the operation is shifted to power supply by the main power generator.

Therefore, it is possible to avoid the stop of the power supply to the private load in the premises due to the power outage of the power system, and it is possible to supply the power stably.

In particular, since electric power is stored in the battery with the DC flowing through the sub-output circuit, and the electric power from this battery is converted into AC by an inverter also provided in the sub-output circuit,
An auxiliary power source can be formed with a simple configuration in which a battery and a second switch for controlling charging and discharging of the battery are provided.

3) In the cogeneration system having the uninterruptible function, the first switch and the second switch are each formed by a semiconductor switching element, so that the semiconductor switching element is compared with a mechanical switch. Since there are no moving parts, the operating speed is fast and the service life is long.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A cogeneration system having an uninterruptible power supply according to an embodiment of the present invention will be described below with reference to the drawings.

1 and 2 are circuit diagrams of a cogeneration system having an uninterruptible power supply function according to an embodiment of the present invention. FIG. 1 is a diagram showing a single-line diagram, and FIG. 2 is a system circuit diagram. It is.

As shown in FIG. 1 and FIG. 2, the cogeneration system having the uninterruptible function is a main generator (main power generator) driven by an engine 21E in synchronization with a power supply of a power system of a power company. A) The cogeneration system 5 used in the distributed power supply system 1 for supplying the power of 21G and the power of the sub-generator (sub-generator) 31G for collecting and generating the exhaust gas energy of the engine 21E to the own load. It is.

The sub-generator 31G is constituted by a turbine generator having a turbine driven by exhaust gas, and the heat energy of the exhaust gas is converted into electric energy as a rotating force of the generator.

The main generator 21G and the sub generator 31
G, a main output circuit 20 for the main generator 21G, a sub-output circuit 30 for the sub-generator 31G, and a control circuit 40 as control means for controlling the cogeneration system 5. .

The main generator 21G is driven by the engine 21E to generate power, and the sub generator 31G is
The energy of the exhaust gas discharged from 1E is recovered to generate power.

A power supply circuit 10 for supplying power of the power system to the private load includes a first circuit breaker 11 and a current transformer 41 serving as a power state monitoring sensor in series between the power system and the private load. And the first switch 12 are provided.

The main output circuit 20 is provided with a second circuit breaker 22 and is connected in parallel to a first connection portion 10C between the first switch 12 of the power supply circuit 10 and the private load. Also,
A rectifier circuit 32, an inverter 33, and a transformer 34 are arranged in series to form a sub output circuit 30 for outputting the power of the sub generator 31G to the main output circuit 20.
To the second connecting portion 20C between the second circuit breaker 22 and the first joining portion 10C.

Although the sub output circuit 30 is connected to the main output circuit 20 in the configurations shown in FIGS. 1 and 2, the sub output circuit 30 may be directly connected to the power supply circuit 2 depending on the layout.
0 to directly output the power of the sub generator 31 </ b> G to the power supply circuit 20.

In the present invention, the sub output circuit 30
The second switch 3 arranged in series with the DC voltage unit 30D
6 and a power storage device formed by the battery 35 are connected. At the same time, when the control circuit 40 detects that a power failure has occurred in the power system when the main generator 21G is stopped,
Power is supplied to the private load using the battery 35 as a power supply source via the second switch 36, and control is performed to start the engine 31E and start power generation of the main generator 31G during the power supply.

The control circuit 40 is connected to the main generator 21
The control of G, the control of the inverter 33, the cutoff control by the ON / OFF operation of the first switch 11, and the charge control by the ON / OFF operation of the second switch 36 are performed.

Further, the first switch 12 and the second switch 3
6 are each formed by a semiconductor switching element.

In the cogeneration system 5 having the uninterruptible function having the above-described configuration, when a power failure is detected by the current transformer 41 installed in the power supply circuit 10 of the power system, the control circuit 40 connects the first circuit breaker 11 to A cutoff signal is issued to the first switch 12.

As a result, at the same time as the power system is cut off from the own load, an ON signal is sent to the second switch 36, and the inverter 33 of the sub-output circuit 30 starts output in a form taking over the voltage waveform of the system. This power is supplied from a battery 35 installed in the DC voltage unit 30D.

From the interruption of the system to the start of power supply by the inverter 33, the process is executed in a short time of several milliseconds (ms), so that power to the private load is continuously supplied without being divided.

The control circuit 40 starts the engine 21E while the power is supplied from the battery 35. After the start, the control circuit 40 synchronizes the output power of the inverter 33 with the governor. When this synchronization is established, the second circuit breaker 22 is turned on (turned on), and the operation shifts to power supply from the main generator 21G.

When the engine 21E is started, the sub-generator 31 is activated.
When G starts supplying power and the voltage of the DC unit 30D becomes higher than the voltage of the battery 35, the power supply source to the inverter 33 automatically shifts from the battery 35 to the sub-generator 31G.

When the power failure of the power system is restored and the power supply on the power system side is resumed, the power system and the main generator system are synchronized by the governor. The circuit breaker 11 and the first switch are turned on to return to the system link.

[0041]

As described above, according to the cogeneration system having the uninterruptible power supply function according to the present invention, even when a power outage occurs in the power system when the main power generator is stopped, the power outage can be prevented. Power is supplied to the self-load by the power storage device arranged in the sub-output circuit, and the main power generator is started together with this power supply, so that interruption of the power to the self-load can be avoided, and the power to the self-load is continuously obtained. Can be supplied.

Therefore, it is possible to avoid a stop of the power supply to the private load in the premises due to the power outage of the power system, and it is possible to supply the power stably.

Also, The power is stored in the battery with the DC flowing through the sub-output circuit, and the power from this battery is converted into AC by the inverter also provided in the sub-output circuit. Therefore, the battery and the charging and discharging of this battery are controlled. The auxiliary power source can be formed with a simple configuration in which only the second switch is provided.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of a single-line connection diagram showing a configuration of a cogeneration system having an uninterruptible power supply function according to a first embodiment of the present invention.

FIG. 2 is a system circuit showing a configuration of a cogeneration system having an uninterruptible function of FIG.

FIG. 3 is a circuit diagram showing a configuration of a conventional distributed power supply system.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Distributed power supply system 5 Cogeneration system 10 Power supply circuit 10C 1st connection part 11 1st breaker 12 1st switch 20 Main output circuit 20C 2nd connection part 21E Engine (motor) 21G Main generator 22 Second breaker Reference Signs List 30 auxiliary output circuit 30D DC section 31G auxiliary power generator (turbine generator) 32 rectifier circuit 33 inverter 34 transformer 35 power storage device 35 battery (power storage device) 36 second switch (power storage device) 40 control means

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5G015 GA05 GA15 GA17 HA16 JA52 5G066 JA02 JB03 5H590 AA00 AA30 CA01 CA07 CA26 CD01 CD03 CE01 CE05 EA01 EA05 EA07 EA14 FA01 FA05 FB01 FC11 FC26 FC27 HA02 HA06 JB18

Claims (3)

[Claims] 1. In synchronization with a power supply of a power system of a power company,
In a cogeneration system of a distributed power supply system that supplies power of a main power generator driven by an engine and power of a sub power generator that collects and generates exhaust gas energy of the engine to generate power, A main power generation device to be driven; an auxiliary power generation device that collects energy of exhaust gas discharged from the engine to generate power; and a main power generation device connected in parallel to a power supply circuit of the power system. An output circuit, a sub-output circuit for outputting the power of the sub-generator to the main output circuit or the power supply circuit, and control means for controlling the cogeneration system. The control means detects that a power failure has occurred in the power system when the main power generator is stopped. In this case, an uninterruptible power supply function is provided in which the power storage device is used as a power supply source to supply power to the private load, and control for starting power generation of the main power generation device is performed during the power supply. Cogeneration system. 2. A cogeneration system having the uninterruptible power supply function, wherein a first breaker and a first switch are provided in series between the power system of the power supply circuit and the private load. The main output circuit comprising: a parallel connection to a first connection between the first switch of the power supply circuit and the private load; and a sub output circuit comprising a rectifier circuit, an inverter, and a transformer in series. A second switch, which is formed and connected to a second connection part between the second circuit breaker and the first junction of the main output circuit, and is arranged in series with a DC part of the sub output circuit. The power storage device formed of a battery is connected, and the control unit controls the main power generation device, controls the inverter, shuts off the first switch, and controls the second switch.
The cogeneration system having an uninterruptible power supply function according to claim 1, wherein charging control is performed by a switch. 3. The cogeneration system with an uninterruptible power supply according to claim 2, wherein said first switch and said second switch are each formed by a semiconductor switching element.