JP2010063320A - Method and apparatus for controlling supply and demand for power system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve controllability and economical efficiency by highly efficiently processing an overload of power transmission facilities due to load fluctuation in short and long periods while satisfying operation restrictions of the power system. <P>SOLUTION: An MMI 5 sets an operation limit value 52 for preventing overload which is 98% of an operation limit value 53 of the power transmission facilities 411-41n. An overload prevention section 37 calculates a value for preventing overload when an online flow value of the power transmission facilities 411-41n exceeds the limit value 52 for preventing overload. The overload prevention section 37 achieve to eliminate the overload of the power transmission facilities 411-41n when the load fluctuates in a short period, and compensates the cyclic period for eliminating the overload of the power transmission facilities 411-41n by economical load distribution control when the load fluctuates in a long period. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a power supply and demand control technology that employs an economic load distribution control method, and in particular, a power supply and demand control method and apparatus for improving the controllability and economy while satisfying operational constraints of the power system. It is about.

  The demand (load) of the power system is constantly changing seasonally, temporally, and momentarily. Therefore, in order to efficiently operate the power system, a supply and demand control technique for controlling power supply according to load fluctuations of the power system is indispensable. In power system supply and demand control technology, it is important to accurately grasp load fluctuations and always maintain an appropriate supply and demand balance.

  Regarding power system load fluctuations, it is considered that pulsation components with various vibrations and periods with small variation widths and irregular fluctuation components are superimposed. Divided into three variable components. That is, a cyclic part for minute fluctuations up to a period of several minutes, a fringe part for short period fluctuations from about a few minutes to about a few tens of minutes, and a sustain part for long-period fluctuations of 10 minutes or more.

  Among cyclic components, load fluctuations with a very short period of up to about 20 seconds can be absorbed by the load characteristics of the system. In addition, the load fluctuation from about 20 seconds to several minutes can be automatically adjusted by optimizing the characteristics of the governor of the power plant that operates in a governor-free operation. Further, when the adjustment cannot be achieved by the governor-free control alone, the control sharing for each periodic component is performed at the central power supply command station of the electric power company.

  For load fluctuations with a fluctuation period of several to ten and several minutes, such as fringe, the amount of load fluctuation is larger than that for cyclic parts. Therefore, load frequency control (hereinafter referred to as LFC) is performed at the central power supply command center of the power company. : Load Frequency Control). In LFC, the frequency deviation and the amount of power fluctuation are detected and the output of the generator is adjusted, so that the grid line flow between electric power companies and the frequency of the entire system can be brought close to a specified value.

  In addition, when the fluctuation cycle is extended to become a sustain portion that is a long load fluctuation of more than a dozen minutes, the load fluctuation becomes considerably large, so it can be considered to be part of the change governed by the daily load curve. . Therefore, it is possible to assume a situation where the output changing capability of the power plant is insufficient only by the application of the LFC, and economical load distribution among a plurality of power plants becomes a problem.

  In response to long-term load fluctuations, the power plant is mainly operated by the economy, and the power supply is adjusted by economic load distribution control (ELD; Economic Load Dispatch). In ELD, an ELD value that is a calculation result of economic load distribution is obtained by an ELD schedule calculation unit, and an operation plan of a power plant that is the most economical is executed based on the ELD value.

  The above ELD is widely adopted in power supply and demand control technology, for example, included in a load frequency control system such as Patent Document 1, and a technique based mainly on the “equal fuel cost law” is adopted. . “Equal Incremental Fuel Cost Law” is a method established in the 1950s, and is based on the basic principle that the optimal value is the one where the differentiated values of the fuel cost characteristics of each thermal power generator are equal (non-patent literature). 1). The above LFC and ELD are the most important control functions in the central power supply command center of the electric power company and play a core role in the operation of the electric power system.

  In addition, the power flow value that flows through the power transmission / transformation equipment may exceed the operation limit value set for the power transmission / transformation equipment due to a change in the demand of the power system, work stoppage or accident of the power transmission / transformation equipment included in the power system. is there. This is nothing but an overload in the transmission and substation equipment. The operation limit value of the transmission and substation equipment is determined from the problem of system stability and the like, and is a limit value that must be strictly observed in system operation. Therefore, when an overload occurs, output adjustment is performed to suppress the output of the generator as an overload elimination measure for eliminating the overload of the transmission and substation equipment.

Generally, in overload elimination measures, an effective overload elimination measure is calculated using the so-called sensitivity coefficient, the amount of change in the power flow value of each transmission and substation equipment when the unit output of each generator is changed. It has become.
JP 2008-42961 A "Electrical Engineering Handbook" The Institute of Electrical Engineers of Japan ISBN4-88686-012-5 (P970 to P975)

  However, the following problems have been raised in the power supply and demand control technology of the electric power system adopting the above ELD. In other words, ELD has created the most economical operation schedule for long-cycle load fluctuations, but it has taken into consideration the overload elimination of transmission and substation facilities associated with both short-cycle and long-cycle load fluctuations. There wasn't. In addition, when an overload occurs in the transmission and substation equipment, there is a contradiction between the movement to suppress the generator output by calculating the overload elimination measure and the movement to increase the generator output at the ELD. For this reason, functional cooperation of both sides was indispensable.

  By the way, due to operation restrictions of the power system, it is inevitable that the operation limit value set in the transmission and substation equipment has some degree of difference with the normal power flow value flowing through the transmission and substation equipment. As mentioned above, this is because the operational limit value of the transmission and substation equipment determined from problems such as system stability is the limit value that must be strictly observed in the system operation. This is because there is room in setting the operation limit value so that it is not exceeded.

  However, when power transmission loss is taken into consideration, it goes without saying that it is desirable from the viewpoint of economic efficiency to operate the power system so that the power flow value of the transmission and substation equipment is close to the operation limit of the transmission and substation equipment. Therefore, in the field of power supply and demand control technology, it is always required to operate the power system with a power flow value as close as possible to the operation limit of the transmission and substation equipment while satisfying the operation constraints of the power system.

  The present invention has been proposed in order to solve the above-mentioned problems, and its purpose is to satisfy the operational constraints of the power system, and to transmit and substation equipment accompanying both short-cycle and long-cycle load fluctuations. Power system supply and demand control method that can improve the controllability by efficiently processing the overload of the power system, and can demonstrate excellent economic efficiency by operating the power system at a power flow value close to the operation limit of transmission and substation equipment And providing such a device.

  In order to achieve the above object, the invention of claim 1 includes a step of inputting an output value of a generator in an electric power system, a step of inputting a power flow value of transmission and transformation equipment in the electric power system, and the electric power system. A step of inputting information on the switch in the power supply, a step of monitoring the state of the power system, a step of calculating a total demand from the output value of the generator, a step of creating a predicted total demand, and a previous day operation plan The step of obtaining the ELD value from the operation schedule calculated by economic load distribution control (ELD), and the power flow value of the transmission and substation equipment exceeded the preset operation limit value of the transmission and substation equipment In this case, the power system supply and demand control method including the step of obtaining a calculated value for overload elimination measures has the following characteristics.

  That is, a step of setting an operation limit value for overload prevention that is an operation limit value for preventing the overload in advance, which is a value lower than the operation limit value of the transmission and substation equipment; Including a step of obtaining a calculated value of the overload prevention measure when the power flow value exceeds the operation limit value for overload prevention, and the step of obtaining the calculated value of the overload elimination measure includes a long cycle load fluctuation. In the step of obtaining a calculated value for eliminating the overload of the transmission and substation equipment, and calculating a calculated value of the overload prevention measure, a calculation for eliminating the overload of the transmission and substation equipment accompanying a short cycle load fluctuation is provided. It is characterized by obtaining a value.

  The invention of claim 3 captures the invention of claim 1 from the viewpoint of the device, and includes means for inputting the output value of the generator in the power system, and transmission and substation equipment in the power system. Means for inputting tidal current values, means for inputting information on switches in the power system, means for monitoring the state of the power system, means for calculating the total demand from the output value of the generator, and prediction A means for creating total demand, a means for creating an operation plan for the previous day, a means for obtaining an ELD value from an operation schedule calculated by economic load distribution control (ELD), and a power flow value of the transmission / transformation equipment are preset. In a power supply and demand control apparatus comprising means for obtaining a calculated value for overload elimination measures when the operation limit value of the transmission and substation equipment is exceeded, a value that is lower than the operation limit value of the transmission and substation equipment, and Preventing the load in advance Means for setting an operation limit value for preventing overload, which is an operation limit value for the operation, and calculation of measures for preventing overload when the power flow value of the transmission and substation equipment exceeds the operation limit value for preventing overload Means for obtaining a value, and means for obtaining a calculated value of the overload elimination measure obtains a calculated value for eliminating the overload of the transmission and substation equipment accompanying a long-cycle load fluctuation, and The means for obtaining the calculated value is characterized in that the calculated value for eliminating the overload of the transmission / transformation equipment accompanying short-term load fluctuations is obtained.

  In the invention described in claims 1 and 3 as described above, it is possible to realize overload elimination of the transmission and substation equipment at the time of short cycle load fluctuation by performing calculation for preventing overload in advance. Accordingly, it is possible to complement the periodic period of the overload elimination processing in the transmission and substation equipment by the economic load distribution control at the time of long cycle load fluctuation. As a result, it is possible to reliably eliminate the overload of the transmission and substation equipment accompanying both short cycle and long cycle load fluctuations.

  In the present invention, an operation limit value for preventing overload that is lower than the operation limit value of the transmission and substation equipment is set in advance, and the power flow value of the transmission and substation equipment that exceeds this operation limit value for preventing overload As an overload prevention measure, it is possible to eliminate the excess of the operation limit value for overload prevention. Therefore, it is difficult for a situation in which the power flow value of the transmission / transformation equipment exceeds the operation limit value for overload prevention and further exceeds the operation limit value of the transmission / transformation equipment. As a result, the power system can be operated at a power flow value as close as possible to the operation limit value of the transmission and substation equipment, while satisfying the power system operation constraints.

  Further, the invention according to claim 2 is the power supply and demand control method according to claim 1, wherein the calculated value of the overload elimination measure and the calculated value of the overload prevention measure are stored in an overload countermeasure table. A step of obtaining a calculated value of the overload elimination measure by referring to the overload countermeasure table and obtaining a calculated value of the overload prevention measure. Then, the calculated value of the overload prevention measure is obtained with reference to the overload countermeasure table.

  In the above invention of claim 2, since the calculated values of the overload elimination countermeasure and the overload prevention countermeasure are stored in advance in the overload countermeasure table, the overload elimination countermeasure and the overload prevention countermeasure are implemented. The processing speed is improved, and the computer load can be reduced.

  As described above, according to the power supply and demand control method and apparatus therefor according to the present invention, it is possible to efficiently overload the transmission and substation facilities accompanying both short-cycle and long-cycle load fluctuations while satisfying the operation constraints of the power system. It is possible to improve the controllability by processing well, and to demonstrate excellent economic efficiency by operating the power system at a power flow value close to the operation limit value of the transmission and substation equipment.

(1) Representative embodiment [configuration]
Hereinafter, typical embodiments according to the present invention will be specifically described with reference to FIGS. 1 to 3. This embodiment is an embodiment in the case of adopting ELD, FIG. 1 is a configuration diagram of this embodiment, FIG. 2 is an explanatory diagram showing each processing of this embodiment, and FIG. 3 is an overload countermeasure table of this embodiment. It is explanatory drawing of.

  As shown in FIG. 1, a plurality of generators 401 to 40 n, power transmission / transformation facilities 411 to 41 n, and switches 421 to 42 n are provided inside the electric power system 1. Reference numeral 5 denotes an MMI (man machine interface). In this MMI 5, an ELD operation limit value 51, an overload prevention operation limit value 52, and an operation limit value 53 are set.

  The overload prevention operation limit value 52 is a characteristic operation limit value set in the present embodiment, and is an operation limit value for preventing overload in advance. The operation limit value 52 for preventing overload is set slightly lower than the normal operation limit value 53 determined from a problem of system stability, for example, about 95% of the operation limit value 53, more preferably It is set to about 98%. As a specific numerical example, when the operation limit value 53 is −100 MW to +100 MW, the overload prevention operation limit value 52 is −98 MW to +98 MW.

  The computer 2 side is equipped with means for executing the following functions. That is, as the parts connected to the generators 401 to 40n, there are a generation end total demand calculation unit 27, an online prediction demand unit 28, an ELD schedule calculation unit 30, a generator output value input unit 31, and an LFC calculation unit 36.

  That is, the plurality of generators 401 to 40n and the computer 2 are connected to the power generation end total demand calculation unit 27 and the ELD schedule calculation unit 30 in the computer 2 via the detection signal line 43 and the control signal line 44. Are connected to the generator output value input unit 31 and the LFC calculation unit 36. The ELD schedule calculation unit 30 is connected to the previous day operation plan unit 29.

  Further, the power transmission / transformation facilities 411 to 41n and the computer 2 are connected to the power transmission / transformation facility power flow value input unit 32 in the computer 2 via the signal line 45 for detection, and further connected to the power system monitoring unit 35. Yes. Further, the switches 421 to 42n and the computer 2 are connected to the switch information input unit 33 in the computer 2 via the detection signal line 46, and the switch information input unit 33 is also connected to the power system monitoring unit. 35.

  An overload elimination countermeasure unit 34 and an overload countermeasure table creation unit 38 are connected to the power system monitoring unit 35, and an overload countermeasure table 54 is connected to the overload countermeasure table creation unit 38. The overload countermeasure table 54 is connected with an overload prevention countermeasure section 37 together with the overload elimination countermeasure section 34, and the countermeasure section 34, 37 is connected with the LFC calculation section 36.

Next, each functional unit in the computer 2 will be described in detail.
[Total power generation demand calculator 27]
The power generation end total demand calculation unit 27 is a part that takes in the generator output value from the generator output value input unit 31 to calculate the power generation end total demand, and sends the calculation result to the online prediction demand unit 28.

[Online forecast demand unit 28, previous day operation plan unit 29]
The online forecast demand section 28 is a means for creating a predicted total demand, and the previous day operation plan section 29 is a means for creating a previous day operation plan, and the output from each section 28, 29 is sent to the ELD schedule calculation section 30. Yes.

[ELD schedule calculation unit 30]
The ELD schedule calculation unit 30 is an economic load distribution control means for creating the most economical operation schedule, and an overload elimination measure based on the ELD operation limit value 51 of the transmission / transformation equipment 411 to 41n set in the MMI 5 The ELD value 71 of each of the generators 401 to 40n is obtained as the calculation result of the economic load distribution, and this is given to the LFC calculation unit 36 as a generator target output value candidate.

[Power system monitoring unit 35]
The power system monitoring unit 35 takes in the switch information from the switch information input unit 33, detects a change in the state of the input switch information, and if there is a change in state, This is notified to the load cancellation countermeasure unit 34.

  In addition, the power system monitoring unit 35 takes in the power flow values of the power transmission / transformation facilities 411 to 41n from the power transmission / transformation facility power flow input unit 32 and compares the input power flow values with the operation limit value 53 set in the MMI 5. When the power flow value of the transmission / transformation equipment 411 to 41n exceeds the operation limit value 53, the overload elimination countermeasure unit 34 is notified of the occurrence of overload.

[Overload countermeasure table creation unit 38]
When the overload countermeasure table creation unit 38 receives a notification that the state change has occurred from the power system monitoring unit 35, or does not receive a notification that the state change has occurred from the power system monitoring unit 35 However, in a fixed cycle such as one minute, the online power flow values of each of the power transmission / transformation equipments 411 to 41n are compared with the respective operation limit values 53 set in the MMI 5, and the power flow values exceeding the operation limit values 53 are compared. Check whether there are transmission and substation facilities. As a result, when there is a power transmission / transformation facility with a tidal value exceeding the operation limit value 53, an overload elimination calculation is performed for that tidal value, and a calculation value 73 (generator target output) of the overload elimination countermeasure, which is the calculation result, is calculated. Value VA) is registered in the overload countermeasure table 54.

  Further, the overload countermeasure table creation unit 38 receives a notification from the power system monitoring unit 35 that there has been a state change, and also receives a notification from the power system monitoring unit 35 that there has been a state change. Even when there is no overload, the on-line power value of each of the transmission / transformation equipments 411 to 41n is compared with the operation limit value 52 for preventing overload set in the MMI 5 at a constant cycle such as one minute cycle. It is checked whether or not there is a power transmission / transformation facility having a tidal current value exceeding the operational limit value 52 for prevention. As a result, when there is a transmission / transformation facility with a tidal value exceeding the operation limit value 52 for preventing overload, overload elimination calculation is performed for the tidal value, and the calculated value 72 of the overload prevention measure is the calculation result. (Generator target output value VB) is registered in the overload countermeasure table 54.

[Overload elimination countermeasure unit 34]
The overload elimination countermeasure unit 34 eliminates an overload in response to a sudden change in load due to an accident in the power system 1, and is activated by the power system monitoring unit 35 when an overload occurs. When activated by the power system monitoring unit 35 when an overload occurs, the overload elimination countermeasure unit 34 refers to the overload countermeasure table 54 and calculates a calculated value 73 of the overload elimination countermeasure registered in the overload countermeasure table 54. Select the calculation value 73 (generator target output value VA (k)) of the countermeasure for overload elimination registered in correspondence with the transmission / transformation equipment in which overload has occurred from (generator target output value VA) The selected overload elimination measure value 73 (generator target output value VA (k)) is then passed to the LFC calculator 36. Here, VA (k) is a generator target output value as a calculated value for overload elimination measures for the generator 40k. The generator 40k is one generator among the plurality of generators 401 to 40n, and is selected as an output value control target.

[Overload prevention measures section 37]
The overload prevention countermeasure unit 37 is a part showing the structural features of the present embodiment. The overload prevention countermeasure unit 37 sets each online power flow value of each of the power transmission / transformation equipments 411 to 41n in the MMI 5 at a fixed period such as a 10 second period and registers each overload registered in the overload countermeasure table 54. Compared with the operation limit value 52 for preventing load overload, it is checked whether or not there is a power transmission / transformation facility having a tidal value exceeding the operation limit value 52 for preventing overload prevention. As a result, when there is a power transmission / transformation facility having a power flow value exceeding the operation limit value 52 for preventing overload, the overload prevention countermeasure registered in the overload countermeasure table 54 is referred to the overload countermeasure table 54. Calculation value 72 of an overload prevention measure registered corresponding to the power transmission / transformation equipment having a tidal value exceeding the operation limit value 52 for prevention of overload from the calculated value 72 (generator target output value VB). (Generator target output value VB (k)) is selected, and the selected calculation value 72 (generator target output value VB (k)) for preventing overload is delivered to the LFC calculation unit 36. ing. Here, VB (k) is a generator target output value as a calculated value of an overload prevention measure for the generator 40k.

[LFC calculator 36]
As shown in FIG. 2, the LFC calculation unit 36 takes in each ELD value 71 for each of the generators 401 to 40n sent from the ELD schedule calculation unit 30 at a cycle of 3 minutes. Further, the LFC calculation unit 36, when it is determined that there is a power transmission / transformation facility having a power flow value that exceeds the operation limit value 52 for overload prevention, an overload prevention measure sent from the overload prevention measure unit 37. The calculated value 72 is taken in. In addition, the LFC calculation unit 36 takes in the calculated value 73 of the overload elimination measure transmitted from the overload elimination countermeasure unit 34 when it is determined that there is a power transmission / transformation facility having a tidal value exceeding the operation limit value 53.

  The LFC calculation unit 36 sends the fetched ELD value 71, the calculated value 72 of the overload prevention measure, and the calculated value 73 of the load elimination measure to the target generator. At this time, the LFC calculation unit 36 sends the calculated value 73 for overload elimination countermeasures most preferentially. If there is no calculated value 73 for overload elimination countermeasures, then the calculated value 72 for overload prevention countermeasures is output next. If there is no calculation value 73 for overload elimination countermeasures and no calculation value 72 for overload prevention countermeasures, the ELD value 71 is transmitted.

  For example, when the calculated value 73 of the overload elimination measure is taken in, the LFC calculation unit 36 sends the calculated value 73 of the overload elimination measure to the target generator. In addition, for a generator that is not the generator to which the calculated value 73 of the overload elimination measure is sent, when the calculated value 72 of the overload prevention measure for this generator is taken in, the overload prevention measure is taken. The calculated value 72 is sent to the target generator. Further, regarding a generator that is not a target generator for sending the calculated value 73 for overload elimination countermeasures and is not a target target for sending the calculated value 72 for overload prevention countermeasures, an ELD targeted for this generator is used. When the value 71 is captured, the ELD value 71 is sent to the target generator.

[Calculation method of overload elimination countermeasure value 73 (generator target output value VA)]
The calculation method of the calculation value 73 (generator target output value VA) of the overload elimination countermeasure in the overload countermeasure table creation unit 38 will be described below.

  One transmission / transformation facility among a plurality of transmission / transformation facilities 411-41n is defined as a transmission / transformation facility 41k, and a power flow value Pk of the transmission / transformation facility 41k is set in advance for the transmission / transformation facility 41k. The case where 53 is exceeded is demonstrated. When there are generators 401 to 40n as generators that can eliminate the deviation of the tidal current value Pk of the power transmission / transformation equipment 41k, the deviation of the deviation of the tidal current value Pk of the transmission / transformation equipment 41k can be eliminated from the generators 401 to 40n. A generator that is most effective in overload elimination measures to be performed, that is, a generator having the largest sensitivity coefficient is selected. When the generator 40k has the highest sensitivity coefficient among the generators 401 to 40n, the overload countermeasure table creation unit 38 selects the generator 40k.

Next, the overload countermeasure table creation unit 38 obtains the generator target output value VA (k) of the selected generator 40k by the following equation. That is,
Generator target output value VA (k) = (Plimit (k) −Pk) / Ak + Pgk
Pk: Tidal current value of transmission / transformation equipment 41k Plimit (k): Operation limit value 53 of transmission / transformation equipment 41k
Pgk: Current output value of the generator 40k Ak: Sensitivity coefficient of the generator 40k (Δ tidal current / Δ generator output)

  As shown in FIG. 3, the overload countermeasure table 54 includes an overload monitoring target transmission / distribution facility in the MMI 5, an operation limit value 53 of the overload monitoring target transmission / distribution facility, and an overload prevention operation limit value 52. Registered in advance.

Here, it is assumed that the power flow value of the overload monitoring target power transmission / distribution facility 418 is 1530 and exceeds the operation limit value 53 of 1500. At this time, the overload countermeasure table creation unit 38 selects the generator 402 having the largest sensitivity coefficient as the generator capable of eliminating the deviation amount, and calculates the generator target output value VA (2) of the generator 402. Here, the current output value of the generator 402 is 500, and the sensitivity coefficient is 0.53.
Generator target output value VA (2) = (1500-1530) /0.53+500
= -56.6 + 500
= 443.4

  The same calculation is performed when the power flow value of the overload monitoring target power transmission / distribution facility 413 exceeds the operation limit value of 4000. When the power flow value of the overload monitoring target transmission / distribution facility 413 is 4020, the current output value of the generator 405 having the largest sensitivity coefficient as a generator capable of eliminating the deviation amount is 600, and the sensitivity coefficient is 0.87, The machine target output value VA (5) = 577.0 is calculated.

[Calculation method of calculated value 72 (generator target output value VB) for measures to prevent overload]
The calculation method of the calculation value 72 (generator target output value VB) of the overload prevention measure in the overload countermeasure table creation unit 38 will be described below.

  When the power flow value of the transmission / transformation equipment 411 to 41n deviates from the operation limit value 52 for preventing overload, the generator target output value VB is calculated as a calculated value for measures for preventing overload. A case will be described in which the power flow value Pk of the power transmission / transformation equipment 41k out of the power transmission / transformation equipment 411 to 41n exceeds the overload prevention operation limit value 52 preset for the power transmission / transformation equipment 41k.

  When there are generators 401 to 40n as generators that can eliminate the deviation of the power flow value Pk of the power transmission / transformation equipment 41k, the overload countermeasure table creation unit 38 takes measures to prevent overload from among the generators 401 to 40n. Thus, the most effective generator, that is, the generator having the largest sensitivity coefficient is selected so that the tidal current value is close to the operation limit value 52 for preventing overload.

  Here, when the generator 40k has the largest sensitivity coefficient among the generators 401 to 40n, the overload countermeasure table creation unit 38 selects the generator 40k, and the generator target output value of the generator 40k. VB (k) is obtained by the following equation.

The formula for obtaining the target output value at this time is as follows. That is,
Generator target output value VB (k) = (Pprelimit (k) −Pk) / Ak + Pgk
Pk: Power flow value of transmission / transformation equipment 41k Preprelimit (k): Operation limit value 52 for preventing overload of transmission / transformation equipment 41k
Pgk: Current output value of the generator 40k Ak: Sensitivity coefficient of the generator 40k (Δ tidal current / Δ generator output)
The LFC calculation unit 36 is also a part that performs a calculation for obtaining the regional required power (AR).

Here, it is assumed that the power flow value of the overload monitoring target power transmission / distribution facility 408 is 1490 and exceeds the overload prevention prevention operation limit value 1470 of 1470. At this time, the overload countermeasure table creation unit 38 selects the generator 402 having the highest sensitivity coefficient among the generators 401 to 40n as a generator capable of eliminating the deviation amount, and generates the generator target output value VB of the generator 402. (2) is calculated. Here, the current output value of the generator 402 is 500, and the sensitivity coefficient is 0.53.
Generator target output value VA (2) = (1470-1490) /0.53+500
= -37.7 + 500
= 462.3

  The same calculation is performed when the power flow value of the overload monitoring target transmission / distribution facility 413 exceeds 3920 of the operation limit value 52 for preventing overload. When the power flow value of the overload monitoring target transmission / distribution facility 413 is 3950, the current output value of the generator 415 having the largest sensitivity coefficient as a generator capable of eliminating the deviation amount is 600, and the sensitivity coefficient is 0.87. The machine target output value VA (5) = 565.5 is calculated.

[Process flow]
Next, an example of the flow of various processes executed in the present embodiment having the above configuration will be specifically described with reference to FIG.

<ELD overload elimination processing / flow of arrow A in FIG. 2>
In the ELD overload elimination processing, the ELD schedule calculation unit 30 performs ELD overload determination at a cycle of 3 minutes based on the ELD operation limit value 51 set by the MMI 5. At that time, the ELD schedule calculation unit 30 obtains an ELD value 71 of economic load distribution in consideration of the future time section, and outputs it to the LFC calculation unit 36. The LFC calculation unit 36 outputs the final target output value to the generators 401 to 40n. By such ELD overload elimination processing, the overload of the transmission / transformation facilities 411 to 41n associated with long-period load fluctuations is eliminated.

<Overload countermeasure table creation processing / flow of arrow B in FIG. 2>
In the present embodiment, in order to reduce the load on the computer 2, the overload countermeasure table creating unit 38 performs processing for creating the overload countermeasure table 54 in advance. As a premise process for creating the overload countermeasure table 54, the operation limit value 52 and the operation limit value 53 for preventing overload are set in the MMI 5.

  When the overload countermeasure table creation unit 38 receives a notification that a state change has occurred from the power system monitoring unit 35, or does not receive a notification that a state change has occurred from the power system monitoring unit 35 However, overload determination is performed with respect to each power flow value of the transmission / transformation facilities 411 to 41n based on the operation limit value 53 set by the MMI 5 at a cycle of 1 minute. When any of the power flow values of the power transmission / transformation equipment 411 to 41n exceeds the corresponding operation limit value 53, the deviation of the power flow value for the power transmission / transformation equipment having a power flow value exceeding the operation limit value 53 is eliminated. The overload elimination calculation to be performed is performed, and the calculation result is registered in the overload countermeasure table 54.

  In addition, the overload countermeasure table creation unit 38 has an operation limit value 52 for preventing overload, which is set lower than the operation limit value 53, for example, 98% of the operation limit value 53, in one minute cycle. Based on the above, overload determination is performed for each power flow value of the transmission / transformation equipment 411-41n.

  When any of the power flow values of the power transmission / transformation facilities 411 to 41n exceeds the corresponding operation limit value 52 for preventing overload, the power transmission / transformation of the power value exceeding the operation limit value 52 for preventing overload is performed. An overload elimination calculation for eliminating the deviation of the tidal current value for the equipment is performed, and the calculation result is registered in the overload countermeasure table 54. When the configuration of the power system 1 is changed, the power system monitoring unit 35 can activate the overload countermeasure table creating unit 38 to recreate the overload countermeasure table 54.

<Overload prevention process / flow of arrow C in FIG. 2>
In the overload prevention process, the period of the ELD overload elimination processing period (3 in this embodiment) corresponding to the elimination of the overload associated with the short period load fluctuation and the long period load fluctuation described in the ELD overload elimination process. Min) complementation.

  Here, the overload prevention countermeasure unit 37 performs overload determination for each tidal current value of the transmission / transformation facilities 411 to 41n based on the operation limit value 52 for overload prevention in a cycle of 10 seconds. When any of the power flow values of the transmission / transformation equipment 411 to 41n exceeds the corresponding operation limit value 52 for preventing overload, the overload countermeasure table 54 is referred to and registered in the overload countermeasure table 54. Among the calculated overload prevention measures 72, the overload prevention measure calculation value 72 registered corresponding to the power transmission / transformation equipment having a tidal value exceeding the overload prevention operation limit value 52 is used. Then, the selected overload prevention measure calculation value 72 is sent to the LFC calculation unit 36.

  In this way, the overload prevention countermeasure unit 37 obtains the calculated value 72 of the overload prevention measure, and the LFC calculation unit 36 issues a command to the generators 401 to 40n as the final target output value, thereby generating the generator 401. ˜40n executes output adjustment, and eliminates the overload of the power transmission / transformation equipment 411 to 41n at the time of short cycle load fluctuation. At the same time, it is possible to complement the overload elimination processing cycle in the transmission / transformation facilities 411 to 41n by the economic load distribution control at the time of long-cycle load fluctuation.

  In the present embodiment, the generators 401 to 40n to be subjected to overload countermeasures require the regional required power (AR) calculated by the LFC calculation unit 36 in order to prevent competition with the command to the generators 401 to 40n by the LFC calculation. ) Is not used as a generator for maintaining the supply-demand balance.

<Overload elimination processing / Flow of arrow D in FIG. 2>
In the overload elimination process indicated by the arrow D in FIG. 2, overload is eliminated with respect to a sudden change in load due to an accident in the power system 1 or the like. When an overload occurs, the power system monitoring unit 35 activates the overload elimination countermeasure unit 34, and the power system monitoring unit 35 selects the transmission / transformation equipment among the transmission / transformation facilities 411 to 41n with respect to the overload elimination countermeasure unit 34. You will be notified if an overload has occurred.

  The overload elimination countermeasure unit 34 refers to the overload countermeasure table 54 and corresponds to the transmission / transformation equipment in which the overload has occurred from the calculated value 73 of the overload elimination countermeasure registered in the overload countermeasure table 54. The calculated overload elimination measure value 73 is selected and the selected overload elimination measure value 73 is sent to the LFC calculator 36. In this manner, the overload elimination countermeasure unit 34 obtains the calculated value 73 of the overload elimination countermeasure, and the LFC calculation unit 36 issues a command to the generators 401 to 40n as the final target output value. 40n performs output adjustment and eliminates the overload of the power transmission / transformation equipment 411-41n.

[Function and effect]
According to the present embodiment as described above, the overload prevention measures unit 37 obtains the calculated value of the overload prevention measures, thereby realizing overload elimination of the transmission and substation facilities 411 to 41n that accompanies short cycle load fluctuations. It becomes possible. At the same time, it is possible to complement the periodic period of the overload elimination processing of the transmission / transformation facilities 411 to 41n by economic load distribution control at the time of long-cycle load fluctuation. Thereby, it is possible to eliminate the overload of the transmission / transformation facilities 411 to 41n accompanying both short-cycle and long-cycle load fluctuations, and it is possible to improve controllability while satisfying the operation constraints of the power system 1. Become.

  Moreover, in this embodiment, the power flow value of the transmission / transformation equipment 411-41n is excessive by presetting the operation limit value 52 for overload prevention that is 98% of the operation limit value 53 of the transmission / transformation equipment 411-41n. When the operation limit 52 for preventing load overload is exceeded, the overload prevention countermeasure unit 37 obtains a calculated value of the countermeasure for preventing overload, and the overload prevention operation limit 52 is exceeded. It can be resolved.

  For this reason, it is possible to avoid a situation in which the power flow value of the power transmission / transformation equipment 411 to 41n exceeds the operation limit value 52 for preventing overload. Therefore, there is no fear that the power flow value of the power transmission / transformation equipment 411 to 41n exceeds the normal operation limit value 53 that is larger than the operation limit value 52 for preventing load. As a result, the power system 1 can be operated at a power flow value as close as possible to the operation limit value 53 of the transmission / transformation equipment 411 to 41n while satisfying the operation restrictions of the power system. Thereby, power transmission loss can be suppressed and economic efficiency is remarkably improved.

  Furthermore, in this embodiment, the overload countermeasure table creation unit 38 compares the operation limit value 52 for preventing overload and the power flow values of the transmission / transformation facilities 411 to 41n, and further compares the operation limit value 53 and the transmission / transformation facility 411. It is possible to compare the tidal values of ˜41n, calculate the excess of the tidal values from the limit values 52 and 53, and store and register these calculation results in the overload countermeasure table 54 in advance. . That is, when the overload elimination countermeasure 34 by the overload elimination countermeasure section 34 and the overload prevention countermeasure section 37 by the overload prevention countermeasure section 37 are executed, the processing speed can be greatly increased. Can contribute to reducing the load.

(2) Other Embodiments The present invention is not limited to the above-described embodiments, and the configuration and the like of each portion can be changed as appropriate. For example, as a power supply and demand control device, each functional portion is It may be realized by one computer, or may be realized by a plurality of computers capable of data communication.

1 is a configuration diagram of a first embodiment according to the present invention. Explanatory drawing of the process in 1st Embodiment. Explanatory drawing of the overload countermeasure table in 1st Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Electric power system 2 ... Computer 27 ... Generation | occurrence | production total demand calculation part 28 ... Online prediction demand part 29 ... The previous day operation plan part 30 ... ELD schedule calculation part 31 ... Generator output value input part 32 ... Transmission / transformation equipment power flow input part 33 Switch information input unit 34 Overload elimination countermeasure unit 35 Power system monitoring unit 36 LFC calculation unit 37 Overload prevention prevention unit 38 Overload elimination table creation units 401 to 40n Generators 411 to 41n Transmission / transformation equipment 421-42n ... Switch 43 ... Generator output detection signal line 44 ... Generator control signal line 45 ... Transmission / transformation equipment power flow detection signal line 46 ... Switch information detection signal line 5 ... MMI (man machine) interface)
51 ... ELD operation limit value 52 ... Overload prevention operation limit value 53 ... Operation limit value 54 ... Overload countermeasure table 71 ... ELD value 72 ... Overload prevention measure calculation value 73 ... Overload elimination measure calculation value

Claims (3)

A step of inputting an output value of a generator in the electric power system, a step of inputting a power flow value of a transmission / transformation facility in the electric power system, a step of inputting information on a switch in the electric power system, and the electric power system The step of monitoring the state of the generator, the step of calculating the total demand from the output value of the generator, the step of creating the predicted total demand, the step of creating the previous day operation plan, and economic load distribution control (ELD) Electric power including a step of obtaining an ELD value from the calculated operation schedule, and a step of obtaining a calculated value for overload elimination measures when the power flow value of the transmission / transformation equipment exceeds a preset operation limit value of the transmission / transformation equipment In the system supply and demand control method,
Setting an operation limit value for preventing overload, which is an operation limit value for preventing the overload in advance, which is a value lower than the operation limit value of the transmission and substation equipment;
When the power flow value of the power transmission and substation equipment exceeds the operation limit value for preventing overload, and calculating a calculated value of measures for preventing overload,
In the step of obtaining the calculated value of the overload elimination measure, the calculated value for overload elimination of the transmission and substation equipment accompanying a long cycle load fluctuation is obtained,
In the step of obtaining the calculated value of the countermeasure for preventing overload, a calculated value for eliminating the overload of the transmission and substation equipment accompanying a short-cycle load fluctuation is obtained. Storing the calculated value of the overload elimination measure and the calculated value of the overload prevention measure in an overload countermeasure table;
In the step of obtaining the calculated value of the overload elimination measure, the calculated value of the overload elimination measure is obtained with reference to the overload countermeasure table,
2. The power supply and demand control according to claim 1, wherein in the step of obtaining the calculated value of the overload prevention measure, the calculated value of the overload prevention measure is obtained with reference to the overload countermeasure table. Method. Means for inputting an output value of a generator in an electric power system, means for inputting a power flow value of a transmission / transformation facility in the electric power system, means for inputting information on a switch in the electric power system, and the electric power system Means for monitoring the state of the generator, means for calculating the total demand from the output value of the generator, means for creating the predicted total demand, means for creating the previous day operation plan, and economic load distribution control (ELD) A means for obtaining an ELD value from the calculated operation schedule, and a means for obtaining a calculated value for overload elimination measures when a power flow value of the transmission / transformation equipment exceeds a preset operation limit value of the transmission / transformation equipment In the power supply and demand control system,
Means for setting an operation limit value for preventing overload, which is an operation limit value for preventing the overload in advance, which is a value lower than the operation limit value of the transmission and substation equipment;
Provided means for obtaining a calculated value of overload prevention measures when the power flow value of the transmission and substation equipment exceeds the operational limit value for overload prevention,
The means for obtaining the calculated value of the overload elimination measure obtains the calculated value for eliminating the overload of the transmission and substation equipment accompanying a long cycle load fluctuation,
Means for obtaining a calculated value of the overload prevention measure is configured to obtain a calculated value for eliminating the overload of the transmission and substation equipment accompanying a short-cycle load fluctuation. apparatus.

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