JP2013027285A - Load sharing method of power generator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a plurality of power generators share appropriate loads even when system's power demand prediction is not accurate.SOLUTION: In a load sharing method of a power generator, a demand power pattern in a prescribed period is prepared in advance on the basis of predicted demand power and preset emergency power, operation start order and operation stop order are set to each of a plurality of power generators which are supply sources of the demand power in accordance with output capacity and energy efficiency of the power generators, each section into which the prepared demand power pattern is divided at the level of the demand power is allocated to the output capacity of respective power generators arranged in accordance with the operation start order and the plurality of power generators are started and stopped in the preset order in accordance with the demand power pattern.

Description

  The present invention relates to a generator load sharing system, and more particularly to a generator load sharing system that assigns a system load to a plurality of generators connected to a system.

  As for the control of the power system, centralized control including a main computer and a plurality of sub computers is performed. Here, the main computer calculates the optimal scheduling of each generator output based on the predicted load demand, and gives an instruction to each generator, thereby realizing operation at the optimal cost of each generator, or economic efficiency. System operation taking into account is performed.

  For example, the main computer creates a generator operation plan for forecasting long-term power demand on a daily basis, or medium-term power demand on the order of hours or tens of minutes, and then several minutes or tens of seconds Short-term power demand prediction in order is performed, the operation pattern of the generator is determined, and the load follow-up operation of each generator is enabled by instructing the sub computer.

JP 2010-35321 A

  However, when a plurality of generators distributed in the system are operated in cooperation, it is not easy to determine load sharing, that is, which generator is operated with what output. As described above, prior to the determination of load sharing, for example, a daily power demand is predicted and a generator operation pattern is created, but the power demand is not necessarily accurately predicted. .

  The present invention has been made in view of such problems, and provides a method capable of operating a plurality of generators with an appropriate load sharing even if power demand prediction is not accurate.

  In order to solve the above problems, the present invention employs the following means.

A demand power pattern within a predetermined period is created in advance based on the predicted demand power and preset standby power, and each of the plurality of generators that are the supply sources of the demand power according to its output capacity or energy efficiency , Set the order of operation start and stop operation,
Each section obtained by dividing the created demand power pattern by the level of demand power is assigned to the output capacity of each generator arranged according to the operation start order, and a plurality of generators are preset according to the demand power pattern. Start or stop with.

  Since this invention is provided with the above structure, even if the electric power demand forecast of a system | strain is not accurate, it can share an appropriate load with a some generator.

It is a figure explaining the pattern of the electric power demand of a system. It is a figure explaining the electric power demand pattern and the driving | operation area level of each set generator. It is a figure which shows output sharing in case two base output generators and one variable output generator are provided. It is a figure explaining a load sharing (load allocation) process.

  Hereinafter, the best embodiment will be described with reference to the accompanying drawings. FIG. 1 is a diagram for explaining a power demand pattern (for one day) of a system, where 1 is a predicted value of power demand, and 3 is a power demand obtained by taking reserve power 2 into consideration for the predicted value of power demand. It is a pattern and is determined in consideration of (added to) the reserve power 2 to the daily power demand forecast value 1. The power demand pattern 3 is a one-day power demand pattern in which the generator can output, that is, it can be operated without changing the number of operating units even if the power demand record fluctuates so far.

  Here, when multiple generators can be operated, if you want to reduce the amount of fuel consumed by these generators that can be operated, increase the power generation efficiency of the generators in descending order. Prioritize operation start in descending order of the rated capacity of the generator. In addition, what is necessary is just to make the order of a stop of operation the reverse order to the above.

  FIG. 2 is a diagram showing an example in which the daily power demand pattern 3 and the demand power pattern 3 are divided into demand power levels 4, 5, 6, 7,. is there.

  Of the daily power demand pattern 3 that must be supplied by any of the generators, in a section where the demand increases, this section is divided into demand power levels 4, 5, 6, 7, and the operation section level ( 1), (2), (3), (4) and (5) are set.

  Further, in a section where demand decreases, this section is divided by demand power levels 8, 9, 10, and 11, and operation section levels (1 ′), (2 ′), (3 ′), (4 ′), (5 ') is set.

  In the section where demand increases, the operating section level (1) is the output range of the generator with the highest priority, the operating section level (2) is the total output range of the generator with the second highest priority, and the operating section Level (3) is the total output range of the generator up to the third highest priority, and operation section level (5) is the total output range of the generator up to the fifth highest priority.

  In the section where demand decreases, the operating section level (1 ') is the output range of the generator with the highest priority, and the operating section level (2') is the total output range of the generator with the second highest priority. The section level (3 ′) is the total output range of the generators up to the third priority, and the operation section level (4 ′) is the total output range of the generators up to the fourth priority. In the demand decreasing section, the demand power level is set smaller than the increasing section by the hysteresis indicated by 12 in the figure.

  It should be noted that the number of operating units in each section and the increase / decrease number thereof do not have to be one, and may be plural. Further, the number of operation sections can be set arbitrarily.

  FIG. 3 is a diagram showing output sharing of each generator to be operated. In the example of the figure, a generator connected to the grid is operated with a base output generator A that is operated at a constant output Pa, a base output generator B that is operated at a constant output Pb, and a variable output Pv. This is a variable output generator C to be operated. In addition, it is possible to cope with minute fluctuations in power demand by the instantaneous reserve capacity of each generator.

  There are various methods for assigning the generator to the base output generators A and B or the variable output generator C, such as assigning in order of good fuel consumption or in descending order of output.

  FIG. 3 shows the output sharing when there are two base output generators and one variable output generator. The total output of all the generators is the output Pa of the base output generator A, the base output generator. It is the sum of the output Pb of B and the output Pv of the variable output generator. In FIG. 3, there is a section in which the output of the base output generator B is low. This is because the output of the base output generator B is set so that the output of the variable output generator C does not fall below the lower limit of output. This is because it was suppressed.

  Thus, on the one hand, the power output forecast value for the day is determined by considering the reserve power, and the generator output pattern is determined, and on the other hand, the generator that is being inspected or malfunctioning is excluded. The possible generators are determined, and the priority of operation and stop is determined from the power generation efficiency. In addition, further, an operation section level (load sharing) is determined by assigning generator outputs that can be operated so as to satisfy the output pattern. At this time, the generator to be operated for each level is determined so that the continuity between the operation section levels is maintained, and the tidal flow and voltage fluctuation are normal, and the output of each generator is determined. To do. By such a procedure, it is possible to determine the generator to be operated and the output sharing of the generator.

  FIG. 4 is a diagram for explaining the load sharing process. For example, a daily power demand is predicted or a predicted value is taken in, and an output pattern (demand pattern) of the generator is determined in consideration of reserve power (step S1). An operable generator is determined by, for example, excluding generators that are being inspected or malfunctioning, and priority of operation and stop is determined based on power generation efficiency (step S2).

  Next, the tidal flow rate and voltage fluctuation between the generators when operating according to the load sharing determined by the above-described procedure are calculated, and it is determined whether or not they are within a specified range. As a result, reverse power flow or voltage fluctuation can be suppressed when the generators are distributed and installed in various places. If the tidal flow or voltage fluctuation is not within the specified range, the load sharing of each generator is changed and the tidal flow or voltage fluctuation is recalculated. This recalculation is repeated by changing the load sharing until the tidal flow and voltage fluctuations are within the specified ranges (steps S2, 3, 4, and 5).

  When the tidal flow and the voltage fluctuation are within the specified range, for example, a daily operation pattern of the generator is created based on the load sharing at this time or the operation section level (step S6).

  In operation, if the error between the actual power demand and the predicted power demand is negligible, each generator is operated according to the determined load sharing (the created operation pattern). That's fine.

  If there is an error between the actual power demand and the power demand forecast value, the error is judged at a cycle of about 10 seconds. If there is a significant error, the load sharing is changed according to the actual power demand. Create an operation pattern (changed operation section level) and calculate tidal flow and voltage fluctuation. In addition, it is determined whether or not the calculation result is within the specified range. If it is not within the specified range, the operation section level is changed again. This operation (change of operation section level, calculation of tidal flow and voltage fluctuation and determination of calculation result) is repeated until the tidal flow and voltage fluctuation are within the specified range.

  As described above, according to the present embodiment, the demand power pattern is predicted, and each of the plurality of generators that are the supply sources of the demand power is operated according to the output capacity or energy efficiency, When the order of operation stop is set in advance, and the section in which the power demand pattern is sequentially divided according to the level of demand power is allocated to the output capacity of each generator arranged according to the order of operation start, and the demand power increases Starts sequentially from the generator assigned to the low level section of the demand power, and when the demand power decreases, stops sequentially from the generator assigned to the high level section of the demand power. At this time, in the section where the demand power decreases, the operation of the corresponding generator is stopped when the demand power decreases by a predetermined amount (hysteresis) than in the section where the demand power increases.

  In this way, the generator output pattern is determined in consideration of the reserve power for the input daily power demand forecast value, and the generators that can be operated by excluding generators that are under inspection or malfunctioning. Determine the machine, determine the priority of operation and stop from the power generation efficiency, etc., determine the operation section level by the output pattern and the drivable generator, so that continuity between operation section levels is maintained, In addition, the generator to be operated is determined for each level so that the tidal flow and voltage fluctuations are normal, and the output of each generator is determined and operated. For this reason, the number of operating generators and the output of the generator connected to the grid can be determined without being affected by the power demand prediction error.

1 Power demand forecast value 2 Reserve power 3 Power demand pattern 4-11 Power demand level

Claims (2)

A demand power pattern within a predetermined period is created in advance based on the predicted demand power and preset standby power,
According to the output capacity or energy efficiency of each of the plurality of generators serving as a supply source of the demand power, set the operation start order and the operation stop order,
Each section obtained by dividing the created demand power pattern by the level of demand power is assigned to the output capacity of each generator arranged according to the operation start order,
A generator load sharing system, wherein a plurality of generators are started or stopped in a preset order according to the demand power pattern. A demand power pattern within a predetermined period is created in advance based on the predicted demand power and preset standby power,
According to the output capacity or energy efficiency of each of the plurality of generators serving as a supply source of the demand power, set the operation start order and the operation stop order,
The generated power demand pattern is sequentially divided according to the level of demand power, and the divided sections are assigned to the output capacities of the generators arranged according to the operation start order, respectively.
When demand power increases, it starts sequentially from the generator assigned to the low level section of demand power, and when demand power decreases, it stops sequentially from the generator assigned to the high level section of demand power The operation method of the generator.

Images