JPH05207658A - Power supply method in co-generation facility - Google Patents

Abstract

PURPOSE:To prevent generated power from flowing reversely to power company side by maximizing the generated power while simultaneously minimizing purchased power. CONSTITUTION:Generated power WG from a generator 44 and purchased power WR from a power supply unit 1 of power company are fed as load power. If the load power is higher than the sum of maximum generated power of the generator 44 and the lower limit of purchased power, purchased power is regulated while keeping the generated power of the generator 44 at the maximum level. If the load power is higher than the lower limit of purchased power but lower than the sum of the maximum generated power and the lower limit of purchased power, generated power is regulated while keeping the purchased power at the lower limit level.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply method for a cogeneration facility, and more particularly to a power supply method for a cogeneration facility that maximizes generated power and minimizes purchased power.

[0002]

2. Description of the Related Art In recent years, gas turbine exhaust gas from a gas turbine driving a generator is introduced into an exhaust heat boiler, water is heated by heat energy of the gas turbine exhaust gas to generate steam, and the generated steam is cooled and heated. Various so-called cogeneration facilities used as steam for steaming are being studied.

[0003]

The electric power obtained in the above-mentioned cogeneration equipment is consumed as electric power (load electric power) of various equipment of the cogeneration equipment, but when the plant equipment is operated at the maximum capacity, the cogeneration equipment is operated. The electric power obtained from the equipment may be insufficient, and in this case, the shortage of electric power must be purchased from the electric power company. In order to deal with such a situation, it is necessary to supply the load of the cogeneration facility with both the generated power generated by the generator of the cogeneration facility and the purchased power purchased from the power company. ..

Further, even if the generated power generated by the generator of the cogeneration facility and the purchased power from the power company are applied to the load of the cogeneration facility, the power generation of the generator of the cogeneration facility has a margin, but the power is not enough. If the amount of electric power purchased from the company is large, there is a lot of waste, and if a reverse flow occurs in which the electric power generated by the generator of the cogeneration facility is supplied to the electric power company side, various troubles may occur.

In view of the above situation, the present invention maximizes the power generated by the generator of the cogeneration facility and minimizes the power purchased from the power company, and the power generated by the generator of the cogeneration facility is minimized. The purpose was to prevent the reverse flow to the electric power company side.

[0006]

DISCLOSURE OF THE INVENTION The present invention provides a power supply method in a cogeneration facility for supplying the generated power obtained by a generator of the cogeneration facility as the load power of the cogeneration facility and the purchased power from a power supply device of a power company. At
When the load power is larger than the sum of the maximum generated power of the generator and the lower limit value of the purchased power, which is the lower limit power that does not cause reverse power flow to the purchased power from the power supply device, the power generation The generated power of the machine is maintained at the maximum generated power to adjust the purchased power, and the load power is larger than the lower limit value of the purchased power, but is larger than the sum of the maximum generated power and the lower limit value of the purchased power. If it is smaller, the purchased power is kept at the lower limit value to adjust the generated power. When the purchased power falls to a predetermined value larger than the lower limit value, the generated power is reduced, and when the purchased power falls below the lower limit value or the generated power falls below the lower limit value. May open a circuit breaker provided on the line from the power supply device to the generator.

[0007]

In the present invention, since the generated power can be the maximum generated power and the operation can be performed with the purchased power being the minimum, waste is avoided, and the generated power is reduced when the purchased power falls near the lower limit value. Reverse flow is prevented by reducing
If the purchased power or generated power is below the lower limit,
The circuit breaker is opened to prevent reverse power flow.

[0008]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

1 and 2 (a) (b) (c) show an embodiment of the present invention, in which 1 is provided with a power feeding main line 2 and a power feeding standby line 3 which are connected in parallel with each other. Power supply device on the side of the power company A, 4 is a circuit breaker connected to the power supply main line 2, 5
Is a circuit breaker connected to the power supply backup line 3 and 6 is a power meter for detecting the amount of power supplied from the power company side A to the customer side B through the power supply main line 2 or the power supply backup line 3. is there.

7 is a power receiving main line connected to the power meter 6,
Reference numeral 8 denotes a power receiving standby line connected to the power meter 6, and the power receiving main line 7 and the power receiving standby line 8 are connected in parallel with each other. Further, circuit breakers 9, 10 and transformers 11, 12 as well as circuit breakers 13, 14 are serially arranged in the middle of the power receiving main line 7 and the power receiving standby line 8 from the upstream side in the power feeding direction D toward the downstream side. It is connected to the.

Reference numeral 15 is a power distribution main line connected to the power receiving main line 7 on the downstream side of the circuit breaker 13, 16 is a power distribution main line connected to the power receiving standby line 8 on the downstream side of the circuit breaker 14, and 17
Is a circuit breaker that connects the power distribution main lines 15 and 16
8, 19, 20 are from the power distribution main line 15, and also 21, 21,
2, 23 are connected from the power distribution line 16 to the branched power distribution branch lines, and 24, 25, 26, 27, 28, 29 are connected to the midway portions of the power distribution branch lines 18, 19, 20, 21, 21, 22, 23. Various power consuming devices (loads) of the cogeneration equipment are connected to the power distribution branch lines 18 to 23.

Explaining the system connected to the power distribution branch line 18, for example, 29 is a generated power supply line for supplying generated power obtained by a generator 44 driven by a gas turbine 45, and 30 is generated power. Power supply line 2
Circuit breaker connected to the middle of 9 and 31 are power distribution branch lines 1
Power purchased from 8 and generator power supply line 29 from generator 44
So as to be able to transmit the generated power transmitted via the power distribution line 18, the power supply line connected from the breaker 24 of the power distribution branch line 18 to the breaker 30 of the generated power supply line 29,
33 and 40 are electric power supply branch lines connected to the electric power supply line 31, and 34 and 35 are connected to the ends of the electric power supply branch lines 32 and 33 so that they can be driven by the supplied electric power, for example, cogeneration equipment. , A motor for driving a gas compressor or a hydraulic pump for starting a gas turbine, 36 and 37 are fuses connected to the midway portions of the power supply branch lines 32 and 33,
38 and 39 are switches connected to midway portions of the power supply branch lines 32 and 33 so as to be located downstream of the fuses 36 and 37 in the power supply direction D, and 41 is connected to an end of the power supply branch line 40. A cogeneration auxiliary device adapted to be operated by the electric power supplied by the power supply, 42 is a switch connected to the middle part of the power supply branch line 40, and 43 is a power supply direction D more than the switch 42 in the middle part of the power supply branch line 40. On the other hand, it is a transformer connected so as to be located on the downstream side.

Next, the power control system will be described.
Is a power detector for detecting power (purchased power) W _R from the power feeder 1 of the power company that is connected between the circuit breaker 9 and the transformer 11 of the power receiving main line 7 and flows through the power receiving main line 7. Therefore, the purchased electric power W _R detected by the electric power detector 46 can be given to the arithmetic and control unit 47 as an electric signal.

Reference numeral 48 is electric power (generated electric power) W _G generated by the electric generator 44 which is connected between the circuit breaker 30 of the electric power distribution branch line 18 and the electric generator 44 and is driven by the gas turbine 45.
A power detector for detecting the
The generated power W _G detected by the above can be given to the arithmetic and control unit 47 as an electric signal.

Reference numeral 49 is to match the phase of the voltage and frequency of the purchased power W _R supplied from the power supply device 1 of the electric power company and the generated power W _G generated by the generator 44 driven by the gas turbine 45. An automatic synchronizer, one end of which is connected between the circuit breakers 24 and 30 of the power distribution branch line 18, and the other end of which is connected to a line 50 that connects the power detector 48 and the power distribution branch line 18, the automatic synchronization device 49. Is the arithmetic and control unit 4
It is possible to operate only when the circuit breaker 30 is closed by the command Y ₁ from 7.

Reference numeral 51 is a speed setting device, and the speed setting device 5
1 to the arithmetic and control unit 47 can be given a speed increase command + V ₁ and a speed deceleration command −V _1, and can also be given automatic sync commands Y ₂ and Y ₃ from the automatic synchronizer 49. ..

Reference numeral 52 is an electronic governor which operates in response to a speed setting command V from the speed setting device 51, and 53 is an electronic governor 5.
A fuel flow control valve that opens and closes in response to the operation of 2.
The fuel flow rate control valve 53 is connected to a midway portion of a conduit 54 for supplying fuel to the gas turbine 45,
It is possible to control the flow rate of fuel injected into the combustion chamber of the.

Although not shown, the power receiving standby line 8
A power control system similar to that on the power receiving main line 7 side is also installed on the side.

In the above facility, the generator 44 is driven by the gas turbine 45, and the generated power generated by the generator 44 passes through the generated power feed line 29, the power distribution branch line 18 and the like to the motor of each device of the cogeneration facility. The electric power supplied to the electric power feeding device 1
From the electric power receiving main line 7, the electric power distribution branch line 18, etc. to the motors 34, 35, etc. of each device of the cogeneration equipment.

At this time, the electric power detectors 48 and 46 detect the generated electric power W _G and the purchased electric power W _R, respectively, and the arithmetic and control unit 4
7 corresponding to the load power W _L consumed by the equipment of the cogeneration facility according to each command from the arithmetic and control unit 47, and the power purchased by the power feeder 1 of the power company W _R and the power generation of the cogeneration facility. Power W generated by the machine 44
_G is controlled, and control of these electric powers W _R and W _G is shown in FIG.
With reference to (a), (b) and (c) as well, description will be given below of a case where power is supplied using the power supply main line 2 of FIG.

For example, necessary for each equipment of cogeneration equipment
Load power W_LHowever, as shown in FIG._L1So
The gas turbine 45 of the generator is at time t in FIG. 2 (c).₁
When it is stopped as shown in FIG.
To the power purchase power W detected by the power detector 46_RIs given
Generated power W detected by the power detector 48_GIs zero
Is. Therefore, the command Y is issued from the arithmetic and control unit 47.₁Out
In the system of the power receiving main line 7, the circuit breaker 30 is opened.
The other circuit breakers are closed. The power
Since the system of the power receiving standby line 8 is not used this time, the circuit breaker 1
0 is also open. Therefore, the power supply of cogeneration equipment
Electric power is purchased from the electric power feeder 1 of the electric power company to the electric wire 31.
Power W_ROnly the power is supplied, and the purchased power W_RIs the load power W_L1And so on
W_R= W _{L 1}= W _R1Is.

When the auxiliary equipment of the gas turbine 45 is started to perform gas purging and the gas turbine 45 is started and the start-up is completed, that is, at time X ₁ in FIG. W _G = W _G1 is generated.
For this reason, the electric power detected by the electric power detector 48 is given to the arithmetic and control unit 47 together with the electric power detected by the electric power detector 46, and as a result, the instruction Y ₁ is output to the breaker 30 and the breaker 30 Will be closed. Therefore, the power supply line 31 of the cogeneration facility is supplied with the generated power W _G generated by the generator 44 in addition to the purchased power W _R from the power company. At this time, although not shown, the arithmetic and control unit 47 gives a command to the electric power feeder 1, and the purchased electric power W _{R at} this time is adjusted so that W _R = W _L1 −W _G1 = W _R2. It

When the state in which the electric power generated by the generator 44 is W _G = W _G1 has passed for a predetermined time and a command to increase the generated electric power starts to be given to the arithmetic control unit 47, the arithmetic control unit 47
A speed increase command + V ₁ is output and given to the speed setter 51, and a speed setting command V is output from the speed setter 51 and given to the electronic governor 52.

Therefore, the opening degree of the fuel flow rate control valve 53 is gradually opened by the electronic governor 52, the fuel flow rate supplied from the conduit 54 to the gas turbine 45 increases, and the output of the gas turbine 45 increases. The generated power W _G generated by the generator 44 gradually increases from W _G1 to W _G2 which is the maximum generated power of the generator 44, as shown in FIG.
At this time, since the load power W _L1 has not changed, the purchased power W _R from the power supply device 1 further gradually decreases from W _R2 according to a command from the arithmetic and control unit 47, and after a predetermined time has elapsed, W _R = W _L1 −W _G2 = W _R3 .

When the load power W _L increases from W _L1 to W _L2 as shown at time X ₂ in FIG. 2A while the generator 44 is operating at the maximum generated power W _G2 , in this case , The generator 44 is operating at the maximum generated power W _G2 and cannot generate more power, so the arithmetic and control unit 47
The electric power W _R from the power supply device 1 is increased by W _L2 −W _{L1 in accordance with} the command from W _R2 = (W _L1 −W _G2 ) + W _L2 −
W _L1 = W _L2 −W _G2 = W _R4 .

As described above, the load power W _L1 is generated by the generator 44.
Maximum generated power W _G2 and power W purchased from the power supply device 1
_When it is larger than the sum of the lower limit value W _R5 of _R described later, the generated power W _G is held at the maximum generated power W _G2 and the purchased power W _R is adjusted.

As shown at time X ₃ in FIG. 2A, when the load power W _L decreases to W _L3 and the load power W _L3 is larger than the maximum generated power W _G2 , the generated power W W _G2 is not changed, and the purchased electric power W _R is reduced, and W _R = W _R4 − (W _L2 −W
_L3 ) = W _L2 −W _G2 −W _L2 + W _L3 = W _L3 −W _G2 = W _R5

When the load power W _L further decreases to W _L4 , the above-mentioned purchased power W _R = W _R5 is the lower limit value for the power feeder 1 of the power company (from the cogeneration facility side to the power company side). If it is the lower limit power that does not generate reverse power flow), the purchased power W _R5 cannot be further reduced. Therefore, in this case, the generated power W _G is adjusted and lowered to W _G3 . That is, W _G = W _L4 −W _R5 = W _L4 −W _L3 + W _G2
The generated power W _G of the generator 44 is reduced so that = W _G3 . In this case, the speed reduction command from the arithmetic and control unit 47-
V ₁ is output and given to the speed setter 51.

The load power W _L rises again to W _L5 ,
And load power W _L5 is greater than the sum of the maximum generated power W _G2 and purchased electric power lower limit value W _R5 of the generator 44, that is, when the _{W L5> W G2 + W R5} , maximum generated power W _G The generated power W _R is increased to W _G2 , and the purchased power W _R is W _R = W _L5 −W _G2 =
W _R6 > W _R5 . At time X ₄ , the purchased power W _R increases from W _R5 to W _R6 as shown in FIG. 2C, but this is because the load power W _L is W up to time X _{4. G2} + W
_It is smaller than _R5 and the purchased power W _R = W _R5 , and it is not necessary to increase it, but after time X ₄ , the load power W _L becomes W _G2 +
This is because it becomes larger than W _R5 and it becomes necessary to increase the purchased electric power W _R.

When the load power W _L sharply and drastically decreases from the time X _{5 in} FIG. 2A, the purchased power W _R falls to the lower limit value W _R5 and is kept constant thereafter, so that the generated power W _G Goes down further. When the load power W _L decreases and the generated power W _G decreases to a predetermined power generation W _G4 which is set in advance, the arithmetic and control unit 47 sends a command Y ₁ to the circuit breaker 30.
Is given and the circuit breaker 30 is opened. For this reason,
The generated power W _G obtained by the generator 44 is no longer supplied to the cogeneration facility, and at time X ₆ , the generated power W _G supplied to the cogeneration facility becomes zero. In this way, the circuit breaker 30 is opened because when the generated power W _G drops below W _G4 , a power flow occurs in which the purchased power W _R from the power feeding device 1 flows to the generator 44, which causes the generator 44 to move. This is because it consumes electric power as an electric motor, and is for preventing this.

Even if the circuit breaker 30 is opened, the gas turbine 45 and the generator 44 are continuously driven without stopping, and the purchased power W _R is equal to the load power W _L7 and W _R = W _L6 = W _R7 .

When the circuit breaker 30 is opened after the time X _{7 in} FIG. 2A and a certain time t ₂ or more elapses, and the load power W _L starts to increase again, the power purchased A state in which the purchased electric power W _R8 , which is a predetermined reference in W _R , is equal to or longer than time t
_{When it} continues for ₃ or more, the circuit breaker 30 is closed by a command from the arithmetic and control unit 47, and the generated power W _G is automatically controlled again. Therefore, the load power W _L changes from W _L6 to W _L7.
Until circuit breaker 30 closes again when rising
The purchased power W _R rises as the load power W _L rises,
Power generated by the generator 44 when the circuit breaker 30 is closed W _G = W
_{When G1} comes to be sent to the power supply line 31 of the cogeneration facility, the purchased power W _R is reduced by the generated power W _G = W _G1 as shown by the purchased power W _R9 in FIG. 2B.

Although not shown, for example, when the purchased electric power W _R drops to a predetermined value larger than the lower limit value W _R5 , the generated electric power W _G is decreased to change the electric power from the generator 44 to the electric power feeder 1.
Circuit breaker 30 is opened to prevent reverse flow into the circuit.
Further, when the load power W _L decreases and the purchased power W _R becomes a value lower than the lower limit value W _R5 , there is a possibility that a reverse flow of the generated power W _G to the electric power feeder 1 side of the electric power company may occur. Therefore,
When the purchased power W _R becomes lower than W _{R5, the} circuit breaker 9 is opened by a command from the arithmetic and control unit 47.

In the description of the embodiments of the present invention, the relationship between the output of the generator and the temperature of the outside air taken into the gas turbine is not particularly mentioned, but in the actual operation, the output of the generator is the outside air. As it is affected by temperature,
The maximum output of the generator 44 changes depending on the outside air temperature. However, with the maximum output of the generator changing,
When the power control is performed, the control becomes complicated. Therefore, it is desirable to perform the control in consideration of the outside air temperature so that the maximum output of the generator does not exceed a certain value.

[0035]

According to the power supply method for the cogeneration facility of the present invention, the power generated by the generator of the cogeneration facility can be maximized and the power purchased from the power company can be minimized. It is possible to achieve various excellent effects such as preventing reverse power flow to the electric power company side.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of a power feeding method in a cogeneration facility of the present invention.

FIG. 2 is a graph showing how electric power changes with time, (a) shows a graph showing how load electric power changes, and (b) shows a graph showing how electric power purchased changes.
(C) is a graph showing how the generated electric power changes.

[Explanation of symbols]

1 power supply device 18 power distribution branch line (line) 29 generated power supply line (line) 30 circuit breaker 44 generator W _R power (purchased power) W _G power (generated power) W _L load power W _R1 , W _R2 , _WR3 , _WR4 , _WR6 , _WR7 , _WR8 , _WR9
Purchased power W _R5 Purchased power (lower limit) W _G1 , W _G3 , W _G4 Generated power W _G2 Maximum generated power W _L1 , W _L2 , W _L3 , W _L4 , W _L5 , W _L6 , W _L7 Load power

Claims (2)

[Claims] 1. A power supply method in a cogeneration facility, wherein the generated power obtained by a generator of the cogeneration facility and the purchased power from a power feeder of a power company are used as the load power of the cogeneration facility, wherein the load power is the power generation. If the sum of the maximum generated power of the generator and the lower limit value of the purchased power, which is the lower limit power that does not generate reverse power flow to the purchased power from the power supply device, is the maximum generated power of the generator. If the load power is greater than the lower limit value of the purchased power but smaller than the sum of the maximum generated power and the lower limit value of the purchased power, the purchased power is adjusted by holding the generated power and adjusting the purchased power. A power supply method in a cogeneration facility, characterized in that the generated power is adjusted by holding the power at a lower limit value. 2. When the purchased power falls to a predetermined value larger than the lower limit value, the generated power is reduced, and when the purchased power falls below the lower limit value or the generated power falls below the lower limit value of the generator. The power supply method in a cogeneration facility according to claim 1, wherein a circuit breaker provided on a line from the power supply device to the generator is opened when the power is lowered.