Plant control method and plant control device
The plant control method and device optimize generator power factor adjustment to balance reactive and active power, addressing grid instability from variable renewable energy integration by minimizing active power loss and maintaining voltage stability.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- HITACHI GE NUCLEAR ENERGY LTD
- Filing Date
- 2022-12-21
- Publication Date
- 2026-07-24
AI Technical Summary
The integration of variable renewable energy sources into power grids faces challenges such as supply-demand imbalances, transmission capacity overloads, voltage fluctuations, frequency fluctuations, and instability, which conventional power factor adjustment methods fail to address effectively, leading to increased grid instability and economic inefficiencies.
A plant control method and device that aggregates generator information, sets priorities based on reactive power supply capabilities, and adjusts the power factor of multiple generators to minimize active power loss while supplying reactive power, using generator information aggregation, priority setting, and generator group command signals.
This approach enhances grid stability by reducing active power loss and maintaining voltage stability, thereby supporting higher renewable energy integration with reduced investment costs.
Smart Images
Figure 0007894806000001 
Figure 0007894806000002 
Figure 0007894806000003
Abstract
Description
Technical Field
[0001] The present invention relates to a plant control method and a plant control device.
Background Art
[0002] In order to solve the problem that the distribution line voltage becomes inappropriate when connecting or disconnecting distributed power sources, Patent Document 1 discloses an operation method of a distributed power system having a generator connected or disconnected to a distribution line and a generator control device for controlling the generator. When the generator shifts from the connected state to the disconnected state, a voltage fluctuation limit amount at the connection point is set. The generator control device acquires the output fluctuation amount of the generator and the voltage fluctuation amount at the connection point, and assumes that the output of the generator and the voltage at the connection point fluctuate at the same ratio. Based on the ratio of the reference output of the generator to the output fluctuation amount and the voltage fluctuation amount, an estimated voltage drop at the connection point when the generator shifts from the connected state to the disconnected state is obtained, and it is determined whether the estimated voltage drop is within the range of the voltage fluctuation limit amount. When it is determined that the estimated voltage drop is outside the range of the voltage fluctuation limit amount, the operating power factor of the generator is adjusted to keep the estimated voltage drop within the range of the voltage fluctuation limit amount.
Prior Art Documents
Patent Documents
[0003]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0004] At the 21st Conference of the Parties to the United Nations Framework Convention on Climate Change (COP21) in 2015, the "Paris Agreement" was adopted, outlining a new international framework for reducing greenhouse gas emissions from 2020 onward. Within this framework, Japan aims to reduce its greenhouse gas emissions by 26.0% by 2030 compared to 2013 levels and by 80% by 2050.
[0005] To achieve this goal, the Agency for Natural Resources and Energy, in its 2015 "Long-Term Energy Supply and Demand Outlook," has set a medium-term target of 22-24% for the ratio of renewable energy (RE) in the power source mix by fiscal year 2030.
[0006] Under this policy, Japan is making progress in introducing renewable energy sources (RE), such as solar, wind, biomass, geothermal, and hydroelectric power. The share of RE in Japan's total electricity generation increased from 12% in fiscal year 2014 to 16% in fiscal year 2019, and this share is expected to continue to increase.
[0007] However, it is anticipated that power grids connected to renewable energy sources (REs) will face various challenges, including supply-demand imbalances, transmission capacity overloads, voltage fluctuations, frequency fluctuations, and instability issues. This is due to factors such as the fact that the output of variable renewable energy sources (VREs), such as solar and wind power, is affected by constantly changing weather conditions; the reduction in the number of synchronous generators in thermal power plants reduces grid inertia; and because suitable locations for solar and wind power generation are limited, the transmission capacity required to deliver electricity from VRE generation sites to demand sites increases, making localized transmission line overloads more likely.
[0008] In response to these challenges, grid reinforcement is planned to ensure a stable delivery of VRE (Variable Real Estate) power from supply to demand. However, the enormous costs associated with these grid reinforcement projects are a major concern. Thus, in a situation where stability and economic efficiency must be considered simultaneously, rather than simply increasing the proportion of VRE, it will be crucial to ensure the stability of the power grid while keeping investment costs down by improving the control of existing equipment.
[0009] One example of improving the control of existing equipment is power factor adjustment for generators. Power factor adjustment is the process of adjusting the ratio of active power to reactive power supplied in the electricity generated by a power source.
[0010] Active power refers to the power consumed to operate, for example, household appliances. In contrast, reactive power is not consumed as power, but it has the effect of maintaining the voltage of the power system by being added to and removed from the power source according to the conditions of the system.
[0011] Originally, power companies operate their systems to maximize the proportion of active power, as their primary purpose is to sell electricity. However, with the increasing VRE (variable real energy) leading to a decline in power grid stability, improving grid stability through reactive power is expected to become increasingly important in the future.
[0012] Patent Document 1 describes a distributed power system that calculates an estimated voltage drop at the interconnection point from the generator output and interconnection status to the distribution lines of the distributed power source, and adjusts the operating power factor of the wind turbine.
[0013] As mentioned above, adjusting the power factor of existing generators has the advantage of being a more cost-effective way to address issues such as the shortage of reactive power supply resulting from the increase in the amount of renewable energy connected, compared to installing new equipment.
[0014] However, as described above, since conventional generators have been generating as much active power as possible and utilizing it for power sales, supplying reactive power instead of active power has a demerit for power generation companies in that it results in the loss of power sales opportunities and a deterioration in economic efficiency. Therefore, it is required to reduce the decrease in active power as much as possible while supplying reactive power.
[0015] The present invention provides a plant control method and a plant control device capable of reducing the decrease in active power compared to the prior art while supplying reactive power.
Means for Solving the Problem
[0016] The present invention includes a plurality of means for solving the above problems. For example, it is a control method for a plant including two or more generators, comprising an information aggregation step of aggregating generator information regarding the generators, a ranking setting step of setting the priority of the generator to which a command signal is to be output based on the two or more generator information aggregated in the information aggregation step, and a generator group command step of outputting the command signal for changing the power factor of the generators based on the priority set in the ranking setting step. This refers to information regarding the region where the amount of reactive power supplied is greater than the limit value of the amount of lagging reactive power supplied at the rated capacity of the power factor curves of two or more of the aforementioned generators. and having And, Information regarding the aforementioned region, the active power at the lagging power factor limit at the rated capacity is P ’-P ,
[0017] , ’-P , a , b , b , ’、P , , , , ) / (P , , a , b , a , , When this is the case, it is the increase in reactive power relative to the decrease in active power (P , , , Information regarding ) and , reactive power P b Let P be the active power after the change. a ’、P b When this is the case, it is the increase in reactive power relative to the decrease in active power (P b ’-P b ) / (P a ’-P a Information regarding ) and to do. [[ID=According to the present invention, while supplying reactive power, it is possible to reduce the amount of reduction in active power compared to the prior art. Problems, configurations, and effects other than those described above will be clarified by the following description of the embodiments.
Brief Description of the Drawings
[0018] [Figure 1] It is a configuration diagram of a plant including a plant control device according to Embodiment 1. [Figure 2] It is a configuration diagram of the generator power factor curve according to Embodiment 1. [Figure 3] It is a configuration diagram of a plurality of generator power factor curves according to Embodiment 1. [Figure 4] It is a configuration diagram showing the priority order of generators supplying reactive power according to Embodiment 1. [Figure 5] It is a configuration diagram showing the effects of Embodiment 1. [Figure 6] It is a configuration diagram showing the effects of Embodiment 1. [Figure 7] It is a configuration diagram of the system fault analysis according to Embodiment 2. [Figure 8] It is a configuration diagram showing the priority order of generators supplying reactive power according to Embodiment 2. [Figure 9] It is a configuration diagram of the system fault analysis according to Embodiment 3. [Figure 10] It is a configuration diagram showing the priority order of generators supplying reactive power according to Embodiment 3. [Figure 11] It is a configuration diagram of the system fault analysis according to Embodiment 4. [Figure 12] It is a configuration diagram showing the priority order of generators supplying reactive power according to Embodiment 4. ]>
Modes for Carrying Out the Invention
[0019] ]>Hereinafter, embodiments of the plant control method and the plant control device of the present invention will be described with reference to the drawings. In the drawings used in this specification, the same or corresponding components are denoted by the same or similar reference numerals, and repeated descriptions of these components may be omitted.
[0020] <Example 1> Embodiment 1 of the plant control method and plant control device of the present invention will be described with reference to Figures 1 to 6. Figure 1 is a configuration diagram of a plant including the plant control device according to Embodiment 1, Figure 2 is a configuration diagram of generator power factor curves, Figure 3 is a configuration diagram of multiple generator power factor curves, Figure 4 is a configuration diagram showing the priority order of generators supplying reactive power, and Figures 5 and 6 are configuration diagrams showing the effects of Embodiment 1.
[0021] First, the overall configuration of the plant, including the plant control device, will be explained using Figure 1. Figure 1 is a diagram of the plant configuration including the plant control device 100 according to the first embodiment of the present invention.
[0022] The plant control device 100 shown in Figure 1 is used to determine power factor changes for generators 120, 121, ... of existing power plants (for example, thermal, nuclear, hydroelectric, geothermal power plants, etc.), and includes a generator information aggregation unit 101, a priority setting circuit 102, a generator group command circuit 103, and the like.
[0023] In this plant control device 100, for example, a computer equipped with a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), and a storage unit executes a plant control planning program, thereby realizing the functions of each part.
[0024] In the plant control device 100, the ranking of generators 120, 121, ... is achieved by a generator information aggregation unit 101 that aggregates generator information related to generators 120, 121, ... and a ranking setting circuit 102 that sets the priority order of the generators 120, 121, ... to which command signals are to be sent based on the generator information aggregation unit 101. Based on the priority order set in the ranking setting circuit 102, the generator group command circuit 103 sends command signals to change the power factor of multiple generators 120, 121, ... to the power factor change circuits 104 of the target generators 120, 121, ... and changes the power factor of each generator 120, 121, ....
[0025] Of these parts and circuits, the generator information aggregation unit 101 preferably becomes the main body for executing the information aggregation process, which aggregates generator information relating to generators 120, 121, ...; the priority setting circuit 102 becomes the main body for executing the priority setting process, which sets the priority order of generators 120, 121, ... to which command signals will be issued, based on the two or more generator information aggregated in the information aggregation process; and the generator group command circuit 103 becomes the main body for executing the generator group command process, which outputs command signals to change the power factor of generators 120, 121, ... based on the priority order set by the priority setting circuit 102.
[0026] Signals from the power factor change circuits 104 of generators 120, 121, ... modify the output of generators 120, 121, ... through the amplification circuit 105, pulse phase control circuit 106, thyristor output circuit 107, and damping circuit 108, which are normally present in the control circuits of generators 120, 121, .... In addition, signals from the generator group command circuit 103 are determined by the voltage detection circuit 109 of the external power system, which is the power system, and the reference voltage comparison circuit 110, which compares the difference between the voltage value detected by the voltage detection circuit 109 and the reference voltage value that generators 120, 121, ... must satisfy.
[0027] In this invention, it is important to determine what kind of information is aggregated in the generator information aggregation unit 101 and what kind of indicators are used as the basis for ranking in the ranking setting circuit 102.
[0028] Therefore, as an example, the inventors have devised a generator information aggregation unit 101 that aggregates information regarding the shape of the possible output curves of two or more generators 120, 121, ... as generator information, specifically information regarding the region where the amount of reactive power supplied is greater than the limit value of the amount of lagging reactive power supplied at the rated capacity of the power factor curve, and then uses a priority setting circuit 102 to prioritize the supply of reactive power from generators 120, 121, ... where the increase in reactive power relative to the decrease in active power is greater.
[0029] Figure 2 shows the possible output curve 200 for generators 120, 121, ..., which represents the range of changeable ratios between active and reactive power for generators 120, 121, .... The horizontal axis represents active power, and the vertical axis represents reactive power.
[0030] The ratio of active power to reactive power can be adjusted by changing the excitation current of the stators of generators 120, 121, ... by changing the lagging supply amount 201 and the leading supply amount 202. Here, even if the initial value 203 of generators 120, 121, ... is at the position shown in Figure 2, it is possible to change it to a position with a change value 204, for example, within the semicircles ABCD in Figure 2, by a power factor change command.
[0031] Here, ABCD is generally determined by the equipment characteristics of the generators 120, 121, ..., such as the maximum excitation current that can be supplied by the rotor coils of generators 120, 121, ... at AB, the maximum armature current that can be supplied by the stator coils at BC, and the temperature rise of the stator core and the ends of the stator core for CD.
[0032] It is known that the possible output curve 200 for generators 120, 121, ... has a different shape for each generator. Figure 3 shows the difference between the possible output curves of two generators, 120 and 121.
[0033] In the potential output curve of the generator 120, for example, in the region connecting curves A and B of the power factor curve 301A of the generator 120, the shape of the curve is determined by the magnitude of the short-circuit current that flows during a fault in the generator 120. In the region of the curve connecting C and D, the shape is determined by the heat resistance temperature of the iron core of the generator 120.
[0034] In contrast, in the region connecting B and C, the arc is determined as a circular arc drawn centered on the origin of the power factor curves of generators 120 and 121, and there is no difference between generators 120, 121, .... That is, for the solid line portion of the power factor curves 301A and 301B of generators 120, 121, ..., the amount of increase in reactive power when the output of active power decreases is different.
[0035] Therefore, the differences between each of these generators 120, 121, ... are stored in the generator information aggregation unit 101, and the priority setting circuit 102 selects the generators 120, 121, ... that will supply reactive power.
[0036] Specifically, as shown in Figure 3, in the solid line region of the power factor curve 301A of generator 120, when the active power decreases, the increase in reactive power is calculated as (A2-E2) / (B1-E1), where the coordinates of point A are (A1, A2), point B are (B1, B2), and point E is (E1, E2).
[0037] Similarly, when the coordinates of point A' in the power factor curve 301B of generator 121 are (A1', A2'), the coordinates of point B are (B1', B2'), and the coordinates of point E are (E1', E2'), we calculate the increase in reactive power when active power decreases, which is (A2'-E2') / (B1'-E1').
[0038] The calculated values for each of these generators 120, 121, ... are stored in the generator information aggregation unit 101, and the priority setting circuit 102 selects the generators 120, 121, ... that supply reactive power according to the magnitude of (A2-E2) / (B1-E1), (A2'-E2') / (B1'-E1'), ....
[0039] Figure 4 shows the rank display unit 400, which is a specific display unit of the rank setting circuit 102.
[0040] The ranking display unit 400 consists of an individual generator ranking display unit 401 that displays the ranking of generators 120, 121, ... that supply reactive power, an individual generator name display unit 402 that displays the generator name corresponding to the individual generator ranking display unit 401, and information 403 regarding the increase in reactive power relative to the decrease in active power.
[0041] According to this ranking display unit 400, power generators can select generators 120, 121, ... that supply reactive power, thereby selecting generators 120, 121, ... that can supply more reactive power than the decrease in active power.
[0042] Figure 5 illustrates the effects obtained by the configuration of this embodiment.
[0043] As shown in Figure 5, the amount of reactive power supplied from generators 120, 121, ... changes from the reactive power before change 502 to the reactive power after change 503, as shown in the change in reactive power 500, according to the change instruction 501 from the external system. Accordingly, in the conventional configuration, the active power 504 changes from the active power before change 505 to the active power after change 506, but in the configuration of this embodiment, it changes from the active power before change 505 to the active power after change 507, so it can be seen that the amount of change from the active power before change 505 can be made smaller compared to the conventional configuration.
[0044] Finally, the effects of this embodiment's configuration from a power system perspective will be explained using Figure 6.
[0045] As shown in Figure 6, in accordance with the change command 602, the voltage 600 of the power system changes from the pre-change voltage 601 to the post-change voltage 604 in the conventional configuration, whereas in the configuration of this embodiment, it changes to the post-change voltage 603. At this time, the post-change voltage 604 in the conventional configuration falls below the operational target value 605, but in the configuration of this embodiment, it is possible to prevent it from falling below the operational target value 605.
[0046] Next, the effects of this embodiment will be described.
[0047] The plant control method for two or more generators 120, 121, ... according to Embodiment 1 of the present invention described above comprises: an information aggregation step for aggregating generator information relating to generators 120, 121, ...; a priority setting step for setting the priority order of generators 120, 121, ... to which command signals will be issued based on the two or more generator information aggregated in the information aggregation step; and a generator group command step for outputting command signals to change the power factor of generators 120, 121, ... based on the priority order set in the priority setting step.
[0048] This enables the prioritization of generators 120, 121, ... according to their equipment characteristics, and while supplying reactive power, it reduces the amount of active power lost compared to conventional methods. As a result, power generators can contribute to increasing the amount of renewable energy connected to the grid while minimizing the loss of opportunities to sell electricity.
[0049] <Example 2> The plant control method and plant control device according to Embodiment 2 of the present invention will be described with reference to Figures 7 and 8. Figure 7 is a configuration diagram of the grid fault analysis according to Embodiment 2, and Figure 8 is a configuration diagram showing the priority order of generators supplying reactive power.
[0050] In Example 1, the ranking of generators 120, 121, ... displayed in the ranking display unit 400 was determined by the increase in reactive power relative to the decrease in active power. On the other hand, from the perspective of contributing to the improvement of power system stability, the voltage maintenance function for the supply of reactive power changes depending on the configuration of the external system, and therefore, the ranking of the generators 120, 121, ... that start up is expected to change depending on the configuration of the external system.
[0051] Therefore, in this embodiment, the generator information aggregation unit 101 aggregates impedance information from the substation to the generators 120, 121, ... as seen from the substation to which two or more generators 120, 121, ... are connected, and the priority setting circuit 102 sets the priority in order of increasing impedance value. For example, the impedance of the transmission lines 701, 703 is used as the impedance information to the generators 120, 121, .... As a result, when the priority display unit 400 displays the ranking of the generators 120, 121, ..., it displays a priority order that makes it easier to supply reactive power based on the configuration of the external system to which the generators 120, 121, ... are connected.
[0052] Figure 7 shows an example of Example 2. As an example, one method of ranking generators 120, 121, ... is considered using the impedance determined by the length and type of transmission lines 701, 703 that connect the generators 120, 121, ... to the power system.
[0053] For example, in Figure 1, generator 120 is connected to the grid via the impedance 702 of transmission line A. Generator 121 is also connected to the power grid via transmission line B, which has an impedance of 704.
[0054] Since the ease of supplying reactive power is determined by the reciprocal of the impedance, if the impedance 702 of transmission line A is smaller than the impedance 704 of transmission line B, and generators 120 and 121 supply the same amount of reactive power, then the amount of reactive power delivered to the grid from generator 120 will be greater than the amount of reactive power supplied from generator 121. Therefore, selecting generator 120 as the source of reactive power allows for a more efficient supply of reactive power to the grid.
[0055] Figure 8 shows the rank display unit 800, which is a specific display unit of the rank setting circuit 102. The rank display unit 800 consists of an individual generator rank display unit 801 that displays the rank of the generators 120, 121, ... that supply reactive power, an individual generator name display unit 802 that displays the generator name corresponding to the individual generator rank display unit 801, and the impedance 803 of the transmission line to which the generators 120, 121, ... are connected.
[0056] According to this ranking display unit 800, power generators can select generators 120, 121, ... that supply reactive power, thereby selecting generators 120, 121, ... that can supply more reactive power than the amount of active power lost.
[0057] Other configurations and operations are substantially the same as those of the plant control method and plant control device described in Example 1 above, and details are omitted.
[0058] As shown in the plant control method and plant control device of Embodiment 2 of the present invention, by aggregating impedance information from a substation to generators 120, 121, ... connected to two or more generators 120, 121, ..., it becomes possible to prioritize the generators 120, 121, ... according to their connection method to the power grid in power generation operations, thereby reducing the amount of active power reduction compared to conventional methods while supplying reactive power.
[0059] <Example 3> The plant control method and plant control device according to Embodiment 3 of the present invention will be described with reference to Figures 9 and 10. Figure 9 is a configuration diagram of the grid fault analysis according to Embodiment 3, and Figure 10 is a configuration diagram showing the priority order of generators supplying reactive power.
[0060] In Example 2, the impedance of the transmission line to which the generators 120, 121, ... are connected was used to rank the generators 120, 121, ... displayed in the ranking display unit 400. In contrast, since the generators 120, 121, ... must pass through the main transformer in the power plant when connected to the grid, it is thought that the impedance of the main transformer also affects the amount of reactive power supplied.
[0061] Therefore, in this embodiment, the impedance of the main transformers of generators 120, 121, ... is used as impedance information up to generators 120, 121, ... and the priority setting circuit 102 assigns them to a specific order.
[0062] As shown in Figure 9, the generator 900 is connected to the power transmission line via the impedance 901 of the main transformer.
[0063] Figure 10 shows the rank display unit 1000, which is a specific display unit of the rank setting circuit 102. The rank display unit 1000 consists of an individual generator rank display unit 1001 that displays the rank of the generators 120, 121, ... that supply reactive power, an individual generator name display unit 1002 that displays the generator name corresponding to the individual generator rank display unit 1001, and the impedance 1003 of the main transformers of the generators 120, 121, ...
[0064] According to this ranking display unit 1000, power generators can select generators 120, 121, ... that supply reactive power, thereby selecting generators 120, 121, ... that can supply more reactive power than the decrease in active power.
[0065] Other configurations and operations are substantially the same as those of the plant control method and plant control device described in Example 2 above, and details are omitted.
[0066] The plant control method and plant control device of Embodiment 3 of the present invention also provide substantially the same effects as the plant control method and plant control device of Embodiment 2 described above.
[0067] <Example 4> The plant control method and plant control device according to Embodiment 4 of the present invention will be described with reference to Figures 11 and 12. Figure 11 is a configuration diagram of the grid fault analysis according to Embodiment 4, and Figure 12 is a configuration diagram showing the priority order of generators that supply reactive power.
[0068] In Example 2, the impedance of the transmission lines to which the generators 120, 121, ... are connected was used to rank the generators 120, 121, ... displayed in the ranking display unit 400. However, from the perspective of the power system, it is desirable to consider the impedance 1100 of the transformer in addition to the impedance of the transmission lines.
[0069] Therefore, in this embodiment, the impedance of the transformers of the main transformers of generators 120, 121, ... is used as the impedance information up to generators 120, 121, ...
[0070] Figure 11 illustrates the impedance 1100 of the transformer. The impedance 1100 of the transformer has a mechanism to boost the voltage when connecting from a lower voltage system to a higher voltage system. Here, "from a lower voltage system to a higher voltage system" means, for example, boosting from a 220kV system to a 500kV system. The impedance of this transformer is used to assign a priority in the priority setting circuit 102.
[0071] Figure 12 shows the rank display unit 1200, which is a specific display unit of the rank setting circuit 102. The rank display unit 1200 consists of an individual generator rank display unit 1201 that displays the rank of the generators 120, 121, ... that supply reactive power, an individual generator name display unit 1202 that displays the generator name corresponding to the individual generator rank display unit 1201, and the transformer impedance 1003.
[0072] According to this ranking display unit 1000, power generators can select generators 120, 121, ... that supply reactive power, thereby selecting generators 120, 121, ... that can supply more reactive power than the decrease in active power.
[0073] Other configurations and operations are substantially the same as those of the plant control method and plant control device described in Example 2 above, and details are omitted.
[0074] The plant control method and plant control device of Embodiment 4 of the present invention also provide substantially the same effects as the plant control method and plant control device of Embodiment 2 described above.
[0075] <Other> It should be noted that the present invention is not limited to the embodiments described above, and includes various modifications. The embodiments described above are explained in detail for the purpose of clearly illustrating the present invention, and are not necessarily limited to those having all the configurations described.
[0076] Furthermore, it is possible to replace parts of the configuration of one embodiment with parts of another embodiment, and it is also possible to add parts of the configuration of another embodiment to the configuration of one embodiment. In addition, it is possible to add, delete, or replace parts of the configuration of each embodiment with parts of other configurations. [Explanation of Symbols]
[0077] 100... Plant control device 101...Generator Information Aggregation Unit 102... Rank setting circuit 103... Generator group command circuit 104...Power factor changing circuit 105... Amplifier circuit 106...Pulse Phase Control Circuit 107... Thyristor output circuit 108... Damping circuit 109...Voltage detection circuit 110...Reference voltage comparison circuit 120,121,900… Generators 200... Generator's potential output curve 201...Delayed supply 202...progress supply 203... Initial value of the generator 204... Changed value 301A, 301B... Power factor curves 400,800,1000,1200...ranking display section 401, 801, 1001, 1201... Individual generator ranking display section 402, 802, 1002, 1202… Individual generator name display section 403…Information on the increase in reactive power relative to the decrease in active power. 500... Change in reactive power 501... Change instruction from an external system 502...Reactive power before change 503...Reactive power after change 504... Active power 505... Active power before change 506... Conventional modified active power 507... Active power after modification of the present invention 600...Power grid voltage 601...Previous voltage 602... Change Order 603...Modified voltage of the present invention 604...Conventional modified voltage 605…Target value for operation 701, 703… Power transmission lines 702, 704, 803, 901, 1003, 1100, 1203… Impedance
Claims
1. A method for controlling a plant that includes two or more generators, The generator information relating to the said generator includes an information aggregation step of information regarding regions where the amount of reactive power supplied is greater than the limit value of the amount of lagging reactive power supplied at the rated capacity of the power factor curves of two or more said generators, A priority setting step, which sets the priority order of the generators to which command signals are to be issued, based on the two or more generator information aggregated in the information aggregation step, The system includes a generator group command step that outputs a command signal to change the power factor of the generators based on the priority order set in the priority setting step, The information relating to the aforementioned region is defined as the increase in reactive power relative to the decrease in active power, given that P a is the active power and P b is the reactive power at the lagging power factor limit at the rated capacity, and P a' and P b' are the active powers after the change, and (P b' - P b) / (P a' - P a). Plant control method.
2. In the plant control method described in claim 1, In the aforementioned priority setting step, the (P) of different generators ｂ '-P ｂ ) / (P ａ '-P ａ The absolute values of the two are compared, and the priority is set in descending order of the absolute value of the increase in reactive power relative to the decrease in active power. Plant control method.
3. In the plant control method described in claim 1, In the information aggregation step, information on the impedance from the substation to the generators, as seen from the substation to which two or more generators are connected, is aggregated. Plant control method.
4. In the plant control method described in claim 3, The impedance of the transmission line is used as the impedance information up to the generator. Plant control method.
5. In the plant control method described in claim 3, The impedance of the main transformer of the generator is used as the impedance information up to the generator. Plant control method.
6. In the plant control method described in claim 3, The impedance information up to the generator is taken from the impedance of the transformer of the generator's main transformer. Plant control method.
7. In the plant control method described in claim 3, In the priority setting step, the priority is set in order of increasing impedance value. Plant control method.
8. A control device for a plant including two or more generators, The generator information relating to the generator includes an information aggregation unit that aggregates information regarding regions where the amount of reactive power supplied is greater than the limit value of the amount of lagging reactive power supplied at the rated capacity of the power factor curves of two or more generators, A priority setting unit sets the priority order of the generators to which a command signal is to be issued, based on two or more generator information aggregated in the information aggregation unit. The generator group command unit outputs a command signal to change the power factor of the generators based on the priority order set in the priority setting unit, The information relating to the aforementioned region is defined as the increase in reactive power relative to the decrease in active power, given that P a is the active power and P b is the reactive power at the lagging power factor limit at the rated capacity, and P a' and P b' are the active powers after the change, and (P b' - P b) / (P a' - P a). Plant control system.