JP2020043757A - Power supply system - Google Patents

Abstract

To allow for economical power supply, while meeting the same amount of planned value at the same time.SOLUTION: A controller acquires a planned value of transmission electric energy of every unit time for the transmission electric energy, i.e., the electric energy transmitted from a power supply system to a transmission and distribution network in a unit time, calculates an allowance of the transmission electric energy based on the planned value, acquires measurement results of a power measurement device for connection with the transmission and distribution network at a time interval shorter than the unit time, calculates the actual value of transmission electric energy of every unit time based on the measurement results, calculates the prediction value of transmission electric energy of every unit time based on the actual value, and changes supply power of a vapor turbine generator under transmission electric energy conditions that the prediction value is within the allowance.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a power supply system.

  In order to realize a sustainable society that does not rely on fossil fuels for energy, renewable energy power generation such as solar power generation and wind power generation is rapidly spreading. However, the amount of generated power often does not always match the amount of power used. Since the supply and demand balance of electric power must be kept stable at any moment, it is necessary to make up for the difference between supply and demand with another power supply. For this compensation, it is necessary to change charging / discharging by the power storage device and electric power of thermal power or hydroelectric power generation according to the load. These coordination forces are increasingly needed as renewable energy generation increases.

  In recent years, in particular, photovoltaic power generation has been rapidly spread, and this adjusting power has become insufficient. As a result, grid operators are increasingly imposing restrictions on the introduction of photovoltaic power generation and restrictions on the acceptance of generated power, making it difficult for power generators to earn income due to delays in the recovery of investment and a reduction in the operation rate of equipment. Or For this reason, there is a concern that the spread of renewable energy power generation will not increase.

  Grid operators are urging solar power generation companies to install power storage equipment as a way to reduce the restrictions on solar power generation. For a system operator, planned and predictable power generation operation is important, and it suffices if it is possible to suppress the cost for unexpectedly raising and lowering solar power generation due to weather conditions.

  Therefore, it is most desirable that each power generation company make a power generation plan and generate power in accordance with it. In this method, a power generation plan is bidding in advance for a predetermined unit time, for example, every 30 minutes or every hour, on the day before, and the power generation company adjusts the power so that the power generation is performed as planned at the time of actual power generation. Is a mechanism to verify and settle payments later. When the difference between the actual power generation amount and the planned value exceeds an allowable value, a penalty fee is generally imposed on the power generation company. In some cases, the allowable value is set to, for example, 3%.

  Patent Literature 1 describes a method of adjusting the total output of wind power generation and gas turbine power generation. Patent Literature 2 describes a power supply management system that supplements power generation using natural energy and power supply by a gas turbine generator with a change in power generation amount due to weather conditions. Patent Literature 3 describes a power supply system that predicts power consumption and solar power generation, and can effectively use solar power generation even when the predicted value differs from an actual value. Have been.

WO 2014/002274 JP 2015-006078 A JP 2012-222860 A

  However, when a power generation company having solar power generation performs planned power generation, it is necessary to have coordination power on its own. As the adjusting force for private use, a storage battery, a gas turbine power generator, a diesel / gas engine, and the like can be considered as disclosed in Patent Document 1. However, the initial cost of the storage battery is high, and the cost of fuel for gas and diesel is high, so that the power generation company may not be profitable. In addition, since the limit of the rate of change of the adjusting force is determined, the electric energy cannot be adjusted instantaneously.

  In order to solve the above problem, a power supply system according to one embodiment of the present invention includes a power generator connected to a power transmission and distribution network through a power line, and a power device connected to the power transmission and distribution network through a power line. And a control device connected to the generator via a control line, wherein the power supplied or consumed by the power device fluctuates, and the control device transmits the power from the power supply system to the power transmission and distribution network. For the transmission power amount, which is the power amount transmitted per unit time, obtain a plan value of the transmission power amount per unit time, calculate an allowable range of the transmission power amount based on the plan value, and Obtain a measurement result of a power measurement device connected to a power distribution network, calculate a performance value of the transmission power amount per unit time based on the measurement result, and calculate the transmission power amount based on the performance value. Is calculated, and the predicted value is Under the transmission power amount provided that the serial is within the allowable range, to vary the supply power of the generator is configured as.

  In addition to satisfying the same amount as the planned value, power can be supplied economically.

1 illustrates a power supply system according to a first embodiment. 2 shows a control logic of the control device 10. An example of a plan value and an actual value is shown. 9 shows plan values in a modified example. 9 shows a control logic of a control device 10 of a modified example. 6 shows a time change of transmission power. 4 shows a temporal change in transmitted power when the output reduction amount of steam power generation is insufficient. 9 shows a time change of transmission power of a modification. 9 shows a power supply system according to a second embodiment.

    Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all the drawings for describing the embodiments, the same members are denoted by the same reference numerals in principle, and overlapping description will be omitted as appropriate.

  FIG. 1 illustrates a power supply system according to a first embodiment.

  The plant 1 includes a steam power generator 111, a power load 201, a solar power generator 101, and a gas turbine power generator 121 as power equipment. The amount of power generated by each of the steam power generator 111, the solar power generator 101, and the gas turbine power generator 121 is monitored and controlled by the controller 10. The circuit breaker 16 is a connection point (interconnection point) between the plant 1 and an external power transmission and distribution network. When the power in the power measuring device 160 flows from the inside of the plant 1 to the outside, the power is transmitted from the plant 1 to the power transmission and distribution network. The power measuring device 160 sends the current transmission power of the plant 1 to the control device 10. The control device 10 compares the power transmission plan with the power transmission plan at regular intervals. The control device 10 can know the power of the power load 201 by dividing the generated power amount of the steam power generation device 111, the photovoltaic power generation device 101, and the gas turbine power generation device 121 from the measured power amount. . The steam power generator 111, the solar power generator 101, and the gas turbine power generator 121 are connected to the control device 10 via control lines. The steam power generator 111, the power load 201, the photovoltaic power generator 101, and the gas turbine power generator 121 are connected to a power transmission and distribution network via a power line and a circuit breaker 16.

  The steam power generator 111 receives steam from the boiler 301 and generates power. The boiler 301 may be inside or outside the plant 1. In addition to sending steam to the plant 1, the boiler 301 sends process steam 401A, 401B, and 401C to another plant. The boiler 301 achieves high efficiency by increasing the capacity, and when another plant is a chemical plant, the process steam 401 at a constant pressure and temperature is required. The output is constant. For this reason, the boiler 301 sends steam having a constant pressure and temperature to the steam power generator 111.

  The transmission power that can be transmitted from the plant 1 to the transmission and distribution network is “transmission power = steam power generation + photovoltaic power generation−power load + gas turbine power generation”. The power load and the actual amount of power for photovoltaic power generation differ from the plan. Therefore, the transmission power at the interconnection point deviates from the planned value. On the other hand, in the power transfer, a penalty is imposed unless the actual value of the power amount per unit time of 30 minutes to 1 hour is equal to the planned value. For this reason, at the time of actual operation, the control device 10 measures and predicts the power generation in a cycle of a measurement time shorter than the unit time, and adjusts the power in the plant 1 in real time in order to observe the power generation plan of the unit time.

  At this time, the power amount of the actual value is a value obtained by integrating the real-time power per unit time. Control device 10 must suppress the difference between the planned value and the actual value to an allowable value (for example, 3%) or less (transmission power condition).

  In steam power generation and gas turbine power generation, the fuel input amount can usually be controlled, so that power can be generated as planned, and the efficiency is highest when the rated output, that is, the maximum output. Therefore, in the configuration like the plant 1, when the actual value of the photovoltaic power generation is larger than the plan value, it is conceivable to suppress the photovoltaic power generation. On the other hand, in the present embodiment, the control device 10 suppresses steam power generation without suppressing solar power generation. Normally, suppressing steam power generation lowers power generation efficiency and is not economical. However, the focus of this embodiment will be described below.

  In advanced nations and other countries, soaring labor costs have increased domestic manufacturing costs, and the manufacturing industry has moved overseas. Therefore, large chemical plants that previously operated at the maximum utilization rate often stop or stop some operations. In the past, petrochemical complexes generated steam intensively in large-scale boilers and distributed the steam to various chemical plants. However, at present, some plants in the petrochemical complex are shut down, so that the steam of the existing boiler may become excessive. Alternatively, the heat and electricity energy management in the in-house power generation, which had been optimized at the maximum utilization rate, was not properly allocated to the changed thermoelectric balance due to the suspension of part of the plant. It may be surplus.

  Therefore, in the present embodiment, in order to effectively utilize the surplus steam, a steam turbine is installed in the plant to generate electric power, thereby covering the power in the plant and further surplus power to other plants and buildings in the company. And the like, and a power supply system for selling power to a wholesale power market. This makes it possible to operate the existing large-sized boiler with high efficiency and to transmit power not only in the plant but also to other plants, thereby increasing the energy self-sufficiency rate in the company.

  Since a process steam used in a chemical plant or the like requires a constant temperature and a constant pressure, an existing large boiler that generates steam for a plurality of plants also operates at a constant load. For this reason, steam power generation can only operate at a constant output using such process steam. Therefore, in the present embodiment, a steam bypass valve 311 is provided in the steam intake path (piping) of the steam power generator 111. Based on an instruction from the steam bypass valve 311 and the control device 10, the steam is released from the inside of the steam intake path to the outside. The control device 10 controls the opening of the steam bypass valve 311 and adjusts the steam pressure from the boiler 301 to adjust the output of steam power generation. The steam bypass valve 311 is connected to the control device 10 via a control line. In addition, the control device 10 controls the steam bypass valve 311 to increase the output change speed of the steam power generation device 111 as compared with controlling the boiler.

  At this time, when the steam generator 111 is operating at the maximum load and the measured value of the power measuring device 160 is likely to be larger than planned, the steam bypass valve 311 is opened, and the power generation of the steam turbine is started. Suppress. As a result, it is not necessary to suppress the photovoltaic power generation device 101, so that it is possible to increase the power of the photovoltaic power generation whose power selling price is higher than that of the steam power generation, thereby increasing the income of the power generation company. At this time, the surplus steam is discarded. Needless to say, the surplus steam can be used for another purpose such as heating.

  On the other hand, when the actual value is likely to be less than the planned value, the control device 10 compensates for the output by the gas turbine power generation device 121 or the like because the output of the steam power generation operating at the maximum load cannot be increased. For example, the control device 10 does not include the gas turbine power generation in the plan, and activates the gas turbine power generation only when there is a shortage, so that the fuel cost occurs only when there is a shortage with the plan and the running cost can be suppressed. . As described above, the feature of the present embodiment lies in that, when the difference between the planned value and the actual value of the generated power amount is compensated in real time, the power source in charge is changed depending on the shortage and the surplus.

  FIG. 2 shows the control logic of the control device 10.

  The control logic shown in this figure shows the output adjustment priority, the output adjustment direction, and the actual value property for each type of power generation device. The output adjustment priority indicates a priority for adjusting the power generation device. The output adjustment direction indicates a direction in which the output is adjusted. For example, when the output adjustment direction of the power generation device indicates “decrease”, it indicates that the power generation device can reduce the output. The actual value property indicates whether or not the actual value of the output of the power generation device matches the planned value. For example, when the actual value property indicates “mismatch”, it indicates that the actual value of the output of the power generation device does not match the planned value.

  In the present embodiment, when a difference between the planned value and the actual value is predicted, the control device 10 controls the steam power generation with the highest priority in order to correct the difference. The control device 10 suppresses the control of the steam power generation mainly when a surplus occurs. If the amount of suppression is not enough even if the steam power generation is suppressed, the control device 10 suppresses the solar power generation. In this case, the control device 10 reduces the output by controlling the inverter of the photovoltaic power generation. By suppressing steam power generation in preference to photovoltaic power generation and shortening the photovoltaic power generation output limit as much as possible, the power generation company can secure a high revenue from power sales.

  Next, when it is predicted that the power transmission amount will be insufficient, the control device 10 gives priority to the steam power generation if there is enough power, and if there is no remaining power, compensates for the power generation by gas turbine power generation. Since steam power generation has high output and high efficiency, it is better to plan at maximum output when planning power transmission. Therefore, it is difficult to further increase steam power generation when power transmission is insufficient during actual power transmission. Therefore, another power source is required. Other power sources include a gas turbine generator 121 (GT), a gas engine generator, a diesel generator, a storage battery, and the like. Thereby, the fuel cost of another power source can be reduced. If other power supplies are being driven, it goes without saying that the control device 10 can cope with the shortage of power transmission and the surplus by using them.

  As a last resort in the case of insufficient power transmission, there is a method of reducing power consumption by disconnecting the power load. For example, the control device 10 may control the power load, or may transmit a power consumption suppression request to a power load manager.

  FIG. 3 shows an example of the planned value and the actual value.

  In this figure, the dotted curve indicates the planned value, and the solid curve indicates the actual value.

  Here, the planned value of the steam power generation (steam power generation device 111) is constant at the maximum output. The plan value of the photovoltaic power generation (photovoltaic power generation device 101) is calculated based on the weather forecast. The plan value of the power load (power load 201) is calculated based on past results. The control device 10 sums up all the plan values to create a power transmission plan, and controls each power supply in accordance with the power transmission plan during actual power transmission. During the period from 7:00 to 11:00, the actual value of the photovoltaic power generation is larger than the planned value, so the control device 10 suppresses the steam power generation. During the period from 12:00 to 15:00, the actual value of the power load is larger than the planned value, and the transmittable amount is insufficient. Therefore, control device 10 increases the output of the other power source (gas turbine power generation device 121). In the period from 15:00 to 19:00, the power load becomes smaller than planned, and the actual value of power transmission becomes more than the planned value, so that the control device 10 suppresses steam power generation. By performing such control, the fuel required for the other power source can be minimized, and the excess steam can be effectively used. In addition, by controlling steam power generation and other power sources according to fluctuations in power supply or consumption of power devices such as photovoltaic power generation and power loads, it is possible to satisfy the same planned value simultaneously.

  FIG. 4 shows plan values in the modification.

  An upper limit value and a lower limit value of the output adjustable range are set in advance for the power generated by each power generator. The planned output value of the steam power generation (steam power generation device 111) is set above the median value of the output adjustable range. The planned value of the output of the other power generation (gas turbine power generation device 121) is set below the median of the output adjustable range. Accordingly, when the output is reduced, a large decrease in the output of the steam power generation can be ensured, and when the decrease in the output of the steam power generation is insufficient, the output of another power generation can be reduced. In addition, when the output is increased, a large increase in the output of the other power generation can be ensured, and when the increase in the output of the other power generation is insufficient, the output of the steam power generation can be increased.

  FIG. 5 shows a control logic of the control device 10 according to the modification.

  In the control logic of the modified example, the set value of the output adjustment direction is different from the control logic of the first embodiment. Here, the output adjustment direction “decrease (main)” indicates that when the output is reduced, the output of the power generation device is mainly reduced. The output adjustment direction “decrease (sub)” indicates that the output of the sub power generation device is reduced when the output is reduced and the amount of decrease in the output of the main power generation device is insufficient. When the output adjustment direction is “increase (main)”, it means that when the output is increased, the output of the power generation device is mainly increased. The output adjustment direction “increase (sub)” indicates that when the output is increased and the amount of increase in the output of the main power generator is insufficient, the output of the sub power generator is increased.

  In the example of this figure, when reducing the output, the control device 10 first reduces the output of steam power generation, and when the amount of reduction is insufficient, reduces the output of other power generation. When increasing the output, the control device 10 first reduces the output of the other power generation, and increases the output of the steam power generation when the amount of increase is insufficient.

  Next, a specific example of control by the control device 10 will be described.

  FIG. 6 shows a time change of the transmission power.

  In this figure, the horizontal axis represents time, and the vertical axis represents transmitted power from the power supply system to the outside.

  The unit time is 30 minutes. Each of the time from time t1 to t2 and the time from t2 to t4 is 30 minutes. The integral value of the planned value of the transmitted power for 30 minutes is the planned power amount, which is the area of the area surrounded by the rectangle of “plan”. On the other hand, the actual value of the transmission power curve is indicated by a solid line of “actual”, and the actual power amount, which is the actual value of the transmission power amount, is the area of the area below the transmission power curve. Since the area of the area A is equal to the area of the area B, the actual electric energy in the period from the time t1 to the time t2 is as planned. However, the control device 10 predicts that the actual electric energy is greater than the planned electric energy after time t2. Therefore, control device 10 starts reducing the output of the steam power generation at t3 between times t2 and t4. What determines t3 is the maximum value of the output change rate of steam power generation (maximum change rate, maximum change speed). In ordinary steam power generation equipment, the output change rate (hereinafter, ramp rate) of several% / min is the largest. Therefore, in consideration of the maximum ramp rate of the steam power generation facility, it is necessary to start suppressing the power of the steam power generation from time t3 so that the area of the area C and the area E are the same. Such a prediction is similarly performed for the gas turbine power generation device 121 as another power supply facility. The control device 10 can match the actual power amount with the planned power amount by predicting the actual power amount and adjusting the output in advance in consideration of the ramp rate of the power supply for adjusting the transmission power amount.

  FIG. 7 shows a time change of the transmission power when the output reduction amount of the steam power generation is insufficient.

  As shown in this figure, when the difference between the planned value and the actual value is large and the area of the area F and the area of the area G cannot be equal between t2 and t4 even when the output change rate of the steam power generation is maximized. It is possible. In this case, the control logic of the above-described modified example may be used.

  FIG. 8 shows a time change of the transmission power of the modification.

  In this case, the control device 10 increases the maximum rate of change using steam power generation and other power generation. In this case, other power generation uses a gas turbine power generation device 121, a gas engine, a diesel engine, or the like having a larger output change rate than the steam power generation device 111. Thereby, the control device 10 can equalize the area of the area Fa and the area of the area Ga between t2 and t4, and can match the planned power amount and the actual power amount per unit time.

  According to the present embodiment, a power generation company having a renewable energy generator such as a photovoltaic power generation can operate the same amount of planned values at the same time and supply power economically.

  Note that the power supply system may perform planned power generation for each unit time, which is the total power of the photovoltaic power generator, the power load, and the power generation using the steam not used as the process steam in the plant. At the time of actual operation, the power supply system periodically measures and predicts the power generation in a cycle shorter than the unit time in order to keep the difference from the plan within a predetermined range, and the integrated value of the power generation in the unit time is If it is likely to exceed, the steam power generation will be given priority over other power generation facilities.

  In addition, the power supply system is composed of a photovoltaic power generator, a power generator that uses steam that is not used as process steam in the plant, and a power generated by removing the power load from the total power of the power generator using a different fuel. May be planned for every certain unit of time. At the time of actual power generation, the power supply system periodically measures and predicts the amount of power generation with a cycle shorter than the unit time, and adjusts the output of the successive power generator while evaluating the difference from the predetermined power generation plan by the integrated value Then, control is performed to keep the difference from the planned value within an allowable value. The power generation amount is mainly controlled by the steam power generation device, and the power generation amount is compensated mainly by the power generation device or power source using fuel other than steam.

  In addition, the power supply system may generate planned power for each unit time, excluding the power load from the sum of the power of the solar power generation and the power of one or more power supplies. At the time of actual power generation, the power supply system periodically measures and predicts the power generation amount in a cycle shorter than the unit time, and adjusts the output of the successive power supply while evaluating the difference from the predetermined power generation plan by the integral value. Control to keep the difference from the planned value within the allowable value. In this case, the power integrated value per unit time is predicted in consideration of the maximum value of the change speed of the output of the power supply, and the output of the power supply is corrected based on the predicted value.

  One of the power sources is a power generation device using steam that is not used as process steam in the plant. One of the other power sources has a higher output change rate than the steam power generator. When the power supply system cannot perform the scheduled adjustment by steam power generation alone, the adjusted output is supplemented by another power source.

  Here, a case will be described in which one business entity manages a plurality of business establishments.

  FIG. 9 illustrates a power supply system according to the second embodiment.

  The power supply system according to the second embodiment includes a plant 1B, an office building 2, and a control device 10B. The plant 1B and the office building 2 are managed by one company. As compared with the plant 1 of the first embodiment, the plant 1B of the second embodiment does not include the solar power generation device 101. The office building 2 includes a power load 201A and a solar power generation device 101. The plant 1 </ b> B transmits power to the office building 2 through the transmission and distribution line 20. The company plans the total power of the plant 1B and the office building 2.

  In this case, in the office building 2, the generated power is shifted from the plan due to solar power generation. The enterpriser adjusts the total transmission power of the plant 1B and the office building 2 by controlling the generated power of the plant 1B so that a penalty is not imposed due to the excess or deficiency of the power. The control device 10B controls the steam power generation device 111, the gas turbine power generation device 121, and the power loads 201A and 201B for excess or shortage in the same manner as the control device 10 of the first embodiment.

  According to this embodiment, the business operator can make the self-consigned transmission of power between the plurality of business establishments, thereby adjusting the actual value of the total transmitted power amount of the plurality of business establishments to the plan value.

  The steam turbine generator corresponds to the steam power generator 111, the steam bypass valve 311 and the like. The steam turbine corresponds to the steam power generator 111 and the like. The adjusting device corresponds to the steam bypass valve 311 and the like. The power device corresponds to the power load 201, the solar power generation device 101, and the like. The power supply corresponds to the gas turbine generator 121 and the like. The power measuring device corresponds to the power measuring device 160 and the like. The allowable range corresponds to a range of the actual value in which the difference between the actual value and the plan value is equal to or less than the allowable value. The first supply power range corresponds to the output adjustable range of the steam power generation device 111 and the like. The second supply power range corresponds to an output adjustable range of the gas turbine power generation device 121 and the like. The first equipment corresponds to the plant 1B and the like. The second facility corresponds to the office building 2 or the like.

  Although the embodiment of the present invention has been described above, this is an exemplification for describing the present invention, and is not intended to limit the scope of the present invention to the above configuration. The present invention can be implemented in other various forms.

  1, 1B: Plant, 2: Office building, 10, 10B: Control device, 16: Circuit breaker, 20: Transmission and distribution line, 101: Solar power generation device, 111: Steam power generation device, 121: Gas turbine power generation device, 160 ... power measuring device, 201, 201A ... power load, 301 ... boiler, 311 ... steam bypass valve, 401 ... process steam

Claims (4)

A power supply system,
A generator connected to the grid via power lines,
Power equipment connected to the grid via a power line,
A control device connected to the generator via a control line,
With
The power supplied or consumed by the power device fluctuates,
The control device includes:
For the transmission power amount that is the power amount to be transmitted per unit time from the power supply system to the power transmission and distribution network, a planned value of the transmission power amount per unit time is obtained,
Calculating an allowable range of the transmission power amount based on the plan value,
Obtain a measurement result of a power measurement device connected to the power transmission and distribution network,
Based on the measurement result, calculate the actual value of the transmission power amount per unit time,
Based on the actual value, calculate a predicted value of the transmitted power amount,
Under the transmitted power amount condition that the predicted value is within the allowable range, the supply power of the generator is changed,
Is configured as
Power supply system. A power supply system,
A generator connected to the grid via power lines,
Power equipment connected to the grid via a power line,
A control device connected to the generator via a control line,
With
The power supplied or consumed by the power device fluctuates,
The control device includes:
For the transmission power amount that is the power amount to be transmitted per unit time from the power supply system to the power transmission and distribution network, a planned value of the transmission power amount per unit time is obtained,
Calculating an allowable range of the transmission power amount based on the plan value,
At a time interval shorter than the unit time, obtain a measurement result of a power measurement device connected to the power transmission and distribution network,
Based on the measurement result, calculate the actual value of the transmission power amount per unit time,
Based on the actual value, calculate a predicted value of the transmission power amount per unit time,
Under the transmitted power amount condition that the predicted value is within the allowable range, the supply power of the generator is changed,
Is configured as
Power supply system. The power supply system according to claim 1 or 2,
A power supply system comprising a storage battery connected to the power transmission and distribution network via a power line and connected to the control device via a control line. The power supply system according to claim 3, wherein
The storage battery supplies power based on an instruction from the control device,
The power supply system, wherein the control device changes supply power of at least one of the generator and the power supply under the transmission power amount condition.

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