JP2004032983A - Power supply system and its operating method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make it possible for a consumer to supply electric power at low cost using a private power-generating facility. <P>SOLUTION: A monitoring and controlling device 22 on the premises collects the data of electric power consumed by a load device 40 at the interval of a prescribed time. Furthermore, the data of weather, temperature and the like are added to forecast required electric power (demand) in the prescribed time. In compliance with the demand, the operation or stop of a power-generating device 30 is determined in such a way as to minimize power-supplying cost and to determine the output of the device 30 when operated. As a result, electric power purchased from a general electric utility can be suppressed low throughout day and night and in all seasons. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a power supply system and an operation method thereof, and more particularly to a power supply system suitable for a combination of operation of a power generation device in a customer and purchase of power from a power transmission and distribution system and an operation method thereof.
[0002]
[Prior art]
In general, most of the electricity consumed by consumers is supplied by general electric utilities (for example, electric power companies), and the rates are divided into basic rates according to the contract type and electricity rates (according to the amount of electricity used) based on the electricity supply agreement. Calculated by sum. Here, the customer refers to the one that receives power from the power transmission and distribution system to the load with the power receiving point with the power transmission and distribution system as a responsibility demarcation point.
[0003]
By the way, there is a case where a consumer who has a load that consumes a substantially constant amount of power throughout the day and night has an in-house power generation facility and obtains electricity at a lower cost than purchasing electricity from a general electric power company. In addition, a cogeneration system (cogeneration) may be performed in a consumer who uses a large amount of heat such as steam or hot water.
[0004]
On the other hand, many customers who need high-quality power without power failure or instantaneous voltage drop are often equipped with uninterruptible power supplies or private power generation facilities. Further, in a building or the like in which a large number of information communication devices are installed, there is a problem that data is lost in the devices due to a power failure or a voltage drop. In particular, when the power consumption of the equipment that needs to be protected is large, the uninterruptible power supply equipment becomes enormous, so that the private power generation equipment may be used together.
[0005]
[Problems to be solved by the invention]
In general, the cost of power supply by in-house power generation facilities is lower than when purchased from a general electric power company, but the power consumption of general consumers varies greatly day and night and seasonally. It is necessary to have a large amount of power, or set a large contract maximum power with a general electric power company. In this case, even if it has a private power generation facility, there are many cases where there is almost no effect of reducing the power supply cost.
[0006]
As a method for coping with a change in power consumption, for example, OHM2000 / 7, As shown in 44-48, a method of starting and stopping the power generator at a preset time is used.
[0007]
The present invention has been made in view of the above points, and an object of the present invention is to provide a power supply system and a method of operating the power supply system that can reduce the power supply cost even in a consumer whose power consumption varies greatly depending on day, night, season, and the like. Is to provide.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, according to the present invention, information on power consumption in a load device is sequentially collected, and a required power (demand) after a predetermined time is predicted based on the collected information on a load. The operation or stop of the power generation equipment is determined so that the supply cost is minimized (if the power generation equipment is operating, its output is determined). In particular, by operating and stopping multiple power generation facilities according to the load characteristics of consumers, the power purchased from general electric utilities can be kept low throughout the day and night and throughout the season, resulting in economical power supply. Will be possible. Further, by predicting the required power (demand) after a predetermined period of time by adding information such as weather and temperature to the collected load information, the required power in accordance with environmental changes such as weather and temperature can be predicted. Can be.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of a power supply system according to the present invention will be described with reference to the drawings.
[0010]
FIG. 1 is a schematic diagram illustrating the configuration of the device according to the present embodiment. In the figure, a customer 1 receives power from a 66 kV transmission and distribution system 10, and the received power is reduced to 3.3 kV by a transformer 3 via a power measuring device 104 and an interconnection protection device 2. The secondary side of the transformer 3 is connected to a bus 11 via a circuit breaker 4, and the bus 11 is connected to a power generator 30 via a power generator communication breaker 8 and a power generator output end circuit breaker 9.
[0011]
The power supplied from the bus 11 via the circuit breaker 5 to the secondary substation on the premises via the circuit breaker 5 is supplied and further reduced in voltage by the transformer 6 and supplied to the load 40 via the circuit breaker 7 for wiring. Is done. In addition, a reactive power adjusting device 50 is also connected to the bus 11.
[0012]
The interconnection protection device 2 includes a protection relay (current, voltage, frequency, ground fault), an islanding detection device, and a circuit breaker.
[0013]
The power generation devices 30 (four) are monitored and controlled by the power generation monitoring and control device 31, and perform control of the prime mover, start / stop of the synchronous generator, parallel operation, reactive power control, and the like. In addition to the power generation monitoring and control device 31, status signals of the transformer and the circuit breaker are collected by the monitoring and control device 22 via the local communication line 21. Also, a control signal is sent from the monitoring control device 22 to each device as needed. The monitoring control device 22 can also communicate with off-premises via the communication line 20.
[0014]
FIG. 2 is a block diagram illustrating a configuration of the monitoring control device 22. The device 22 sequentially collects information on the power consumption of the load 40 at predetermined time intervals of, for example, 5 minutes or more and 30 minutes or less, and after a predetermined time based on the collected information, for example, 5 minutes or more and 30 minutes or less. A communication device 231 and an arithmetic processing device 232 for performing demand forecasting, optimizing the output of the power generating device, etc., an input device 233, and a display device 234 as information collecting means for predicting the required power after a predetermined time. Have been. Various databases (hereinafter abbreviated as DB) are connected to the arithmetic processing unit 232. The various DBs include a load / operation status information DB, a maintenance information DB, and a cost information DB. The arithmetic processing device 232 is connected to a remote input / output device 275 via a private communication network. The remote input / output device 275 captures a status signal of each device in the premises and outputs a control signal to each device. The display device 234 displays a load state, a power generation device operation status, a voltage / power factor / power flow, a switch state, a demand prediction, a power generation device command value, a device abnormality, a maintenance instruction, and the like.
[0015]
FIG. 3 is a block diagram illustrating the configuration and operation of the arithmetic processing device 232. The arithmetic processing device 232 includes a status signal receiving unit 251, a control signal generating unit 252, an arithmetic processing unit 253, a memory unit 254, and a communication function unit 255 for performing communication with off-premises.
[0016]
The status signal receiving unit 251 receives a load device status signal (# 1 to #n) signal, a power generator status signal (# 1 to #m), a voltage / power factor monitor signal, a switch status signal, and a device abnormality signal. Given. The load device state signal includes the power consumption of the load and serves as base data for demand prediction. The equipment abnormality signal includes combustion abnormality and temperature abnormality of the prime mover (diesel engine), abnormal vibration and insulation abnormality of the generator, insulation abnormality of the substation equipment and interconnection equipment, and the like.
[0017]
Based on the information obtained by the state signal receiving unit 251, the arithmetic processing unit 253 performs demand prediction and optimization of the power generation device output, and generates a control signal based on the result. Specifically, it issues a power generator control signal (# 1 to #m), an invalid voltage regulator control signal, and a switch control signal (including load control), which are command values of the governor and the voltage regulator. , And controls each device. The result of the control is monitored by the monitoring control device 22.
[0018]
FIG. 4 is a flowchart illustrating the processing of the monitoring control device 22. In this example, the processing shown in the flowchart of FIG.
[0019]
As shown in the figure, first, the weather, temperature, electricity bill and fuel bill are updated to the latest time step values (1201). Next, the latest load demand is obtained by load monitoring (1202), and is accumulated in the load / operation state information DB (1203). The demand after 10 minutes is predicted using the neural network method based on the time change of the load, the weather, and the temperature (1204). When the neural network method was applied to the time change (load curve) of the actually measured load, it was confirmed that it could be predicted with an error of 5% or less.
[0020]
The time interval for updating the control value is determined by the required accuracy of prediction and the time required to start and stop the power generator. To prevent reverse power flow to the grid, the time interval is set to 30 minutes or less, typically 10 minutes or 5 minutes.
[0021]
In order to meet the above demand, power generation by the on-site power generation equipment and power purchase from the transmission / reception and distribution system will be covered, but the power generation amount and the power purchase ratio are determined so that the power supply cost is almost minimized. Specifically, optimization was performed by applying a linear programming method using the power supply cost as an objective function (1205). However, in the present embodiment, it is assumed that there is no reverse power flow, that is, the power generated in the premises is consumed by the load device in the premises and is not passed to the power transmission and distribution system. Based on the result of the above optimization, the operation of the power generator is started / stopped, and in the case of operation, the output is set (1206). Based on the monitoring result of the voltage / power factor (1207), the setting of the voltage regulator is performed (1208).
[0022]
When an abnormality of a device, especially a power generation device is detected (1209), it is recorded in a maintenance information DB (1210), and it is checked whether or not the power generation device can be switched (1211). The calculation is performed, and the output is set again (1213). If switching is not possible, load selection cutoff is performed according to a predetermined priority (1212). Actually, in some cases, it is possible to avoid load selection interruption by issuing an alarm before performing load selection interruption and reducing the load.
[0023]
FIG. 5A is an example of power supply in the embodiment of FIG. FIG. 2B shows an example in which power is supplied by a method of starting and stopping the power generator at a preset time, which has been conventionally performed. In each case, four power generators are used. The curves in the figure indicate the power demand, the private power generation amount, and the power purchase amount, respectively.
[0024]
As is clear from the figure, according to the method of the present embodiment (method (a)), the power purchase amount can be reduced by about 30% as compared with the conventional method (b). In this case, the power supply cost was reduced by about 12%.
[0025]
In addition, when operating the power generator, the total operation time of the four power generators can be made substantially equal by operating the power generator from a device having a short total operating time, so that the maintenance and renewal of a specific power generator can be accelerated. Could be prevented.
[0026]
Until now, the explanation has been given of the case where the power generation equipment in the customer is operated efficiently according to the load and the insufficient power is supplied from the general electric power company. It is also possible to supply the house with insufficient power by consignment from a centralized supply center. The power supplied from the centralized supply center will be referred to as “supply power”.
[0027]
FIG. 6 is a schematic diagram showing a configuration of main equipment including the centralized supply center 110. The facilities on the premises of the customer are the same as those in the embodiment of FIG. 1, but for simplicity, only the main equipment is shown. Although only two customers are shown in the figure, power is supplied to the five customers from the centralized supply center.
[0028]
The power generated by the power generator 30 of the centralized supply center 110 is boosted in the substation 102a, transmitted through the transmission line 101, lowered in the substation 102b, transmitted through the transmission and distribution system 10, and supplied to each customer. Supplied. A power measuring device 105 for measuring the amount of power received by the power transmission and distribution system 10 and measuring devices 106a and 106b for measuring the amount of power supplied to each customer are provided.
[0029]
In the centralized supply center 110, five power generators 30 (2000 kW each) are installed as power generation facilities. In the centralized supply center 110, the power generation facilities are adjusted according to the supplementary power supplied to each customer. In addition to deciding whether to start or stop operation, if it is running, its output is determined. The operation status of each power generation device 30 in the centralized supply center 110 is monitored by the centralized monitoring and control device 120.
[0030]
On the other hand, the predicted value of the supplementary power required by each customer required for determining the control value of the power generation equipment in the centralized supply center 110 is calculated by the centralized supervisory control from the supervisory control device 22 via the communication line 20 and the public line 121. Collected in device 120.
[0031]
FIG. 7 is a schematic diagram showing a monitoring screen in the centralized supply center. In the upper part, the predicted demand (352) of each customer (351) under the jurisdiction of the centralized supply center, the self-supplied power (353), the supplementary power that must be supplied to each customer (354), and the consignment at the supply point The power (355), excess / deficiency (356) are displayed, and further, the total supply power (357) and the total committed power are also displayed. In the lower part, the voltage (362), the frequency (364), the phase (364), and the power generation output (365) of each power generation device and the system side (361) installed in the centralized supply center are displayed. Further, the transmitted power at the power receiving point (366) and the deviation (367) between the received power and the supplied power (total) are also displayed.
Normally, the power generation output is adjusted so that the fluctuation range of the transmitted power every 30 minutes is within 3% of the contracted power of the power transmission service.
[0032]
Next, an optimal operation method of the power generator 30 in the centralized supply center 110 according to the present embodiment will be described.
[0033]
FIG. 8 is a diagram for explaining an operation method of the power generation device 30, and schematically illustrates a quantitative relationship among power consumption, power generation, entrusted power, and power generation at the centralized supply center 110 at the customer. .
[0034]
Although there are customers 1 to n, only the customer 1 and the customer j are shown in the figure. Reference numeral 401 denotes power consumption at each customer, 402 denotes power generated by the customer, and 403 denotes transmission power. The generated power 405 of the centralized supply center 110 is shown for each power generation device. The power generated by the power generator k shows as G _k. For simplicity, it is assumed that there is no loss during transportation.
[0035]
In the customer j, the power consumption (L _j ) at the load must be equal to the sum of the generated power (G _j ) of the house and the transmitted power (B _j ). That is, the following equation holds for 1 to n.
[0036]
L _j = G _j + B _j (1)
G _j may be supplied from a plurality of power generators. As described above, each customer operates the power generation device such that the power supply cost is minimized. As a result, the required transmission power for each customer is:
_{B j = L j -G j (} j = 1~n) ... (2)
It becomes.
[0037]
Consider the operation of the centralized supply center 110 for supplying these commissioned powers. The cost Φ required to supply all the consigned power consists of the cost required for power generation, the cost required for consignment, and other costs (e). Assuming that the power generated by the power generator k is G _k , the power generation unit price g _k , the contracted charge rate c, and the contracted basic charge d,
Φ = Σ (g _k × G _k ) + Σ (c × B _j + d) + e (3)
Here, Σ in the first term on the right side represents the sum when k is 1 to m, and Σ in the second term represents the sum when j is 1 to n. Although the second term of the expression (3) changes with time, the generated power (G _k : k = 1 to m) can be determined so that Φ is minimized.
[0038]
By applying this method, the cost of power supply from the centralized supply center 110 to each customer can be kept low, and power can be supplied to each customer at low cost.
[0039]
Further, in the power supply system according to the present embodiment, as shown in FIG. 9, a distributed power system that connects the power transmission and distribution system 10 and each device in the customer is displayed on a display screen of the display device 234 of the monitoring and control device 22. Is displayed, and an information screen and information on the weather, date, temperature, etc. are displayed adjacent to the system diagram 500. As the information screen, for example, a power purchase information screen 501, a power receiving transformer information screen 502, a generator information screen 503, and a load / prediction information screen 504 are displayed. And information by an operator's operation are displayed. For example, the power purchase information screen 501 displays the name of the power company, the type of power, active power, and the like. The generator information screen 503 displays information about the specifications and operating conditions of each generator 30, On the prediction information screen 504, current power consumption, active power, and the like are displayed. When the predicted value of the required power is out of the range of the set value, the load / prediction information screen 504 is displayed so as to blink.
[0040]
Here, when an operation for setting information regarding the power purchase contract and the power receiving transformer is performed, a setting screen regarding a contract with a power company and a setting screen regarding characteristics of the power receiving transformer are displayed as shown in FIG. It has become so. When an operation for setting details of each generator 30 is performed, a setting screen for setting the specifications of the generator 30 and the like is displayed as shown in FIG.
[0041]
On the other hand, when the display of the monitor screen is selected, as shown in FIG. 12, the information on the predicted demand, the total generator output, the power purchase amount, and the actual demand is displayed in a trend display along the time axis. As shown in FIG. 13, when a monitor screen for monitoring the output of each generator 30 is selected, the transition of the output of each generator 30 is trend-displayed along the time axis. Further, as shown in FIG. 14, when information such as power consumption and power purchase for one day is totaled, the arithmetic processing unit 232 evaluates the cost for one day, and the analysis result is displayed on the display unit 234. It is displayed on the display screen.
[0042]
【The invention's effect】
According to the present invention described above, the power purchased from a general electric utility can be kept low throughout the day and night, and the power can be obtained at low cost.
[Brief description of the drawings]
FIG. 1 is a system configuration diagram for describing an embodiment of an operation method of a power supply system of the present invention.
FIG. 2 is a block diagram showing a configuration of a monitoring control device employed in the embodiment of FIG.
FIG. 3 is a block diagram illustrating a configuration of an arithmetic processing unit employed in the embodiment of FIG. 1;
FIG. 4 is a flowchart illustrating a process of the monitoring control device illustrated in FIG. 2;
5A and 5B show examples of power supply according to the present invention and a conventional example, wherein FIG. 5A shows a case of the present invention and FIG. 5B shows a case of a conventional example.
FIG. 6 is a configuration diagram of main equipment including a centralized supply center for explaining another embodiment of the present invention.
FIG. 7 is a diagram showing a monitoring screen in the centralized supply center shown in FIG.
FIG. 8 is a diagram illustrating a method of operating a power generation facility according to the present invention.
FIG. 9 is a diagram illustrating a display example of a system diagram of a power supply system.
FIG. 10 is a diagram illustrating a display example of a setting screen of a power purchase contract / power receiving transformer.
FIG. 11 is a diagram showing a display example of a generator detailed setting screen.
FIG. 12 is a diagram showing a display example of a daily load curve.
FIG. 13 is a diagram showing a display example of a generator monitor screen.
FIG. 14 is a diagram illustrating a display example of an analysis result of cost evaluation.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Consumer, 2 ... Interconnection protection device, 3, 6 ... Transformer, 4, 5 ... Breaker, 7 ... Wiring breaker, 8 ... Generator breaker, 9 ... Generator breaker Reference numeral 10: Power transmission and distribution system, 11: Bus, 20: Communication line, 21: Local communication line, 22: Monitoring and control device, 30: Power generation device, 31: Power generation monitoring and control device, 40: Load, 50: Reactive power adjusting device Reference numerals 101, transmission lines 102a, 102b, substations, 104, power measuring devices, 105, power receiving measuring devices, 106a, 106b, measuring devices, 110, centralized supply centers, 120, centralized monitoring and control devices, 121, public lines .

Claims (19)

A power supply system that supplies power to a load device in a customer by receiving power from a power generation device and a transmission / distribution system installed in a customer premises, and information collection for sequentially collecting information on power consumption in the load device. A power supply system, wherein the information collecting means predicts required power after a predetermined time based on the collected information, and determines whether to operate or stop the power generation equipment according to the prediction result. . A power supply system in which a customer supplies power to a load device in a customer by a transfer from a pre-contracted centralized power supply center and power reception from a power generation device installed in the customer premises, wherein the load device Information collecting means for sequentially collecting information on power consumption of the power generation equipment, wherein the information collecting means predicts required power after a predetermined time based on the collected information, and determines operation or stop of the power generation equipment according to the prediction result. A power supply system, comprising: 3. The power supply system according to claim 1, wherein the information collection unit determines an output of the power generation facility when the power generation facility operates. 4. 4. The power supply system according to claim 1, wherein the information collection unit determines a change in a state of the power generation facility using a power supply cost as an objective function. 5. Power supply system. 5. The power supply system according to claim 1, wherein the information collecting unit obtains a load curve indicating a time change of a load from the collected information on power consumption, and determines the load curve. 6. A power supply system characterized by predicting required power after a predetermined time using a curve as learning data. 6. The power supply system according to claim 5, wherein the information collecting unit collects information on temperature and weather, and uses the collected information as learning data for predicting required power after a predetermined time. Power supply system. The power supply system according to any one of claims 1, 2, 3, 4, 5, and 6, wherein the information collection unit collects information on power consumption in the load device for 5 minutes to 30 minutes. A power supply system characterized by being executed at the following time intervals. A power supply system that supplies power to a load device in a customer by receiving power from a power generation device and a transmission / distribution system installed in a customer premises, and information collection for sequentially collecting information on power consumption in the load device. Means, the information collecting means predicts required power after a predetermined time based on the collected information, and when the predicted value of the required power is out of the range of the set value, displays the fact on a display screen. A power supply system comprising: A power supply system that supplies power to a load device in a customer by receiving power from a power generation device and a transmission / distribution system installed in a customer premises, and information collection for sequentially collecting information on power consumption in the load device. Means, the information collection means predicts the required power after a predetermined time based on the collected information, and displays the prediction result on a display screen, and the power transmission and distribution system and each device in the customer and The power supply characterized in that a distributed power supply system connecting the distributed power supply systems is displayed on a display screen in a system diagram, and an information screen related to the distributed power supply system is displayed on the display screen adjacent to the system diagram. system. 10. The power supply system according to claim 9, wherein the information collecting unit sets information on the distributed power supply system when a setting screen is selected when the information is displayed in a system diagram on the display screen. Power supply system characterized by displaying a setting screen for displaying on a display screen. 10. The power supply system according to claim 9, wherein the information collecting unit is configured to display the system diagram on the display screen when a generator on the system diagram is selected. 11. A power supply system, wherein information on the output of the generator is collected and a transition of the generator output is trend-displayed on a display screen. When operating a power supply system that supplies power to load devices in a customer by receiving power from a power generation device and a transmission and distribution system installed in the customer premises,
A power supply system that sequentially collects information regarding power consumption in the load device, predicts required power after a predetermined time based on the collected information, and determines whether to start or stop the power generation equipment in accordance with the prediction. Operation method. 13. The operating method of the power supply system according to claim 12, wherein when the power generation equipment is operating, an output of the power generation equipment is determined. 13. The power supply system operating method according to claim 11, wherein the predetermined time interval for collecting information on power consumption in the load device is set to 5 minutes or more and 30 minutes or less. . The power supply system according to any one of claims 11, 12, 13, and 14, wherein the power supply cost is an objective function for determining whether to operate or stop the power generation facility or to determine the output when the power generation facility is in operation. An operation method of a power supply system, wherein the method is used as a power supply system. The power supply system operating method according to any one of claims 11, 12, 13, 14, and 15, wherein the power supply system is required after a predetermined time based on information on power consumption in the load device collected at the predetermined time interval. A method of operating a power supply system, wherein a measured load curve is used as learning data to predict power. When a customer operates a power supply system that supplies power to a load device in a customer by a transfer from a centralized power supply center contracted in advance and a power reception from a power generation device installed in the customer premises,
Operation of a power supply system characterized by sequentially collecting information on power consumption in the load device, predicting required power after a predetermined time based on the information, and determining whether to start or stop the power generation equipment in accordance with the information. Method. 18. The operating method of the power supply system according to claim 17, wherein when the power generation equipment is operating, an output of the power generation equipment is determined. 18. The method of operating a power supply system according to claim 17, wherein the centralized power supply center determines whether to operate or stop a power generation device in the center based on information on a load of each customer and power generation power, and in a case of operation. Is a method of operating a power supply system, characterized in that its output is determined.

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