JPH0228599A - Load follow-up operation device for nuclear power plant - Google Patents

Abstract

PURPOSE:To increase the load follow-up operation ability of the power plant to its maximum and to improve the economy and safety of system operation by sending a load follow-up operation control command for the whole power plant from a center load-dispatching office. CONSTITUTION:Each power generation unit calculates an operation range where in load follow-up operation control (DPC) is allowed by a DPC command redistri bution part 205 according to a current operation state. Further, a fast operation range calculation part 225 calculates an operation range wherein fast output variation is possible in the DPC operation range. Further, an adjustment output (AFC) operation calculation part 226 calculates AFC operation width which is allowed with each output within the DPC operation range and finds the relation of the AFC operation width to a base output. Then the DPC command redistribution part 205 use DPC operation ranges, fast operation ranges, and the relations of the AFC operation width to the base output which are found by the units to redistribute the current DPC command values of the respective units so that previously requested fast operation capacity, AFC and governor- free operation capacity are secured.

Description

[Detailed Description of the Invention] [Objective of the Invention] (Industrial Application Field) The present invention is directed to a load following operation control (hereinafter referred to as DPC) command issued from a central power dispatch center to a nuclear power plant and an automatic frequency control command. The adjusted output (hereinafter referred to as AFC) command is appropriately distributed to each unit in the nuclear power plant to control the output, and in the plant state after the output change based on the DPC command, the high speed The present invention relates to a load following operation device for a nuclear power plant that redistributes DPC commands of each unit so that adjustment capacity, AFC capacity, and governor free (hereinafter referred to as GF) capacity can be secured.

(Prior Art) Generally, a central power dispatch center issues a command signal for generator output to each power plant so that the total amount of power generation follows fluctuations in load in the power system. This command signal includes a DPC command that predicts the amount of load fluctuation based on past operating results, etc., and calculates and commands the amount of power generation at each power plant that will be most economically advantageous. There is an AFC command that issues a command to each power plant to finely adjust the difference between the total power generation amount based on the DPC command and the actual load.

If the total power generation amount based on this DPC command does not match the actual load, the system frequency will deviate from the reference value as a result. The above AFC command is actually calculated based on the deviation of the system frequency from the reference value detected at the central power dispatch center and output to each power plant.

In addition, as an operation to adjust the deviation between the amount of power generation and the load, we also use governor-free (CF) control, which adjusts the generator output based on the deviation in system frequency detected at each power plant, without relying on commands from the central dispatch center. ) There is driving. This GF driving is
Since the generator output is directly controlled by the shift in the system frequency, it can respond immediately to load fluctuations, so it is particularly important as a spinning reserve in preparation for sudden large load fluctuations. Furthermore, among the fluctuations in load on -day, especially when there is a sudden rise in the morning, a sudden decrease/increase before and after the lunch break, or when a sudden imbalance between load and power generation occurs due to a system failure, etc.
Operational ability to quickly adjust the amount of power generation is required.

Such load-following operation is currently carried out at thermal power plants and hydroelectric power plants with adjustable output, and only base load operation is carried out at nuclear power plants, but as the amount of power generated by nuclear power plants increases. As a result, there will be an increasing need for load following in nuclear power plants in the future.

(Problems to be Solved by the Invention) However, when the above-described load following operation is performed in a nuclear power plant, there are the following problems.

In other words, if the reactor output is significantly changed in one day due to DPC operation, the accumulated amount of xenone, a fission product in the fuel, will change, which will change the reactivity and reduce the reactor output. Change. Therefore, it is necessary to perform an operation to compensate for this change in the accumulated amount of Zenon and maintain the output at the command value.

In boiling water nuclear power plants, such output change operations and operations to compensate for changes in the amount of Zenon accumulated are mainly performed by controlling the recirculation flow rate and changing the core flow rate. There is a risk of violating the constraints established to ensure the integrity of the system.

FIG. 4 is a diagram showing such constraints imposed on the relationship between the reactor power and the core flow rate, and the shaded area in the figure is the prohibited operation area. In the above-mentioned operation, there is a risk that the vehicle will deviate from the operating range shown in FIG. Furthermore, when the output is increased rapidly, the overshoot of the neutron flux becomes large, so there is a risk that the constraint on the neutron flux will be exceeded near the rated output. Therefore, it is necessary to suppress the rate of increase in output to a low level when the output is 91 or higher, as shown in FIG. 5, for example. In addition, in the case of AFC operation, it is necessary to take the above constraint conditions into account.If the maximum value of output adjustment by AFC is ±5% of the rated output, the AFC operation will be
The operating range in which the maximum range of operation can be performed is shown in FIG. 6, for example. When the operating point is in the region 11 in the figure, the AFC operating width is restricted to 5% or less.

In the case of GF operation, the impact on the reactor is relatively small, so there is little risk of exceeding the constraints imposed to ensure fuel integrity, but GF operation may cause the generator output to fall below the rated value. In order to avoid exceeding the limit, the GF operation had to be carried out, for example, in the operating region 12 shown in FIG.

The present invention was made to solve the above-mentioned problems, and instead of sending the DPC command and AFC command from the central power dispatch center to each unit in the power plant individually, the DPC command for the entire power plant is sent centrally. The generator output adjustment amount for the entire power plant is calculated from the AFC command during AFC operation, and these requested amounts are appropriately distributed to each unit within the power plant.
The object of the present invention is to provide a load-following operation device for a nuclear power plant that can maximize the load-following operation capability of a power plant and greatly improve the economic efficiency and stability of system operation.

[Configuration of the Invention (Means for Solving the Problems) The load following operation device for a nuclear power plant of the present invention has a load following operation device for a nuclear power plant equipped with a plurality of power generation units. a load following operation range calculating means for calculating a load following operation range based on the operating state;
a high-speed operation range calculation means for calculating a high-speed operation range in which the output can be changed at high speed within the calculated load-following operation range;
Adjusted output operating range calculation means for calculating the adjusted output operating range allowable for each output within the load following operation range, and high-speed operating capacity, adjusted output operating capacity, and governor free operation that are required in advance for the nuclear power plant. The load following operation command value of each power generation unit is redistributed to ensure the capacity, and the load following operation distribution rate and adjusted output distribution rate are determined to appropriately distribute the load following operation command and adjusted output command to each generation unit. The present invention is characterized by comprising a load following operation command redistribution means that calculates based on the load following operation capacity and adjusted output operation capacity of each power generation unit after the load following operation command is redistributed.

(Function) The present invention provides, in each power generation unit in a nuclear power plant,
The DPC operation range calculation means calculates an operation range within which DPC operation is permitted based on the current operation state. Also,
A high-speed operation range calculation means is used to calculate an operation range in which the output can be changed at a particularly high speed in the above-mentioned DPC operation range. Further, the AFC operation width calculation means calculates the AFC operation width allowable at each output within the DPC operation range to determine the relationship between the base output (DPC command value) and the AFC operation width. DPC calculated for each of these units
Using the relationship between the operation range, high-speed operation range, and base output versus AFC operation width, the DPC command redistribution means calculates the high-speed operation capacity, AFC operation capacity, and GF requested from the central power dispatch center to the nuclear power plant in advance. The current DPC command values of each unit are redistributed to ensure operating capacity.

Further - DP at the output state of each unit after redistribution
From the C operating capacity and AFC capacity, calculate the DPC distribution rate and AFC distribution rate of each unit in order to appropriately distribute the subsequent DPC command and AFC command for the power plant to each unit.

By using the above means, it is possible to maximize the load following operation capability of the power plant, and the contribution to the economic efficiency and stability of system operation can be greatly increased.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 is a diagram for explaining a load following operation device in a nuclear power plant, which is an embodiment of the present invention.

The load following operation method of this embodiment is aimed at improving the load following operation performance of the entire power plant in a nuclear power plant having multiple units.
The DPC command 111 and AFC command 112 from 01 assume that the command values for the entire nuclear power plant are sent to the power plant, rather than the respective required values being sent directly to individual units. It is assumed that the input unit 201 and the A, FC command manual unit 202 receive the DPC command 111 and the AFC command 112, respectively.

DPC command input section 201 and AFC command input section 202
After checking whether the DPC command 111 and AFC command 112 from the central power dispatch center 101 are normal, the command values are sent to the unit DPC command creation section 20.
3 and the unit AFC command creation section 204. In the unit DPc command creation section 203, the sent DPC
The command value is compared with the previous command value, and if there is a difference, the DPC command redistribution means is used in advance in DPC command redistribution #205 in order to adjust the output of the entire power plant to compensate for the difference. Calculated DPC allocation rate 21 for each unit
0 is used to calculate the DPC command value 213 for each unit and send it to each unit.

In addition, the unit AFC command section 204 calculates the generator output adjustment amount for the entire power plant based on the AFC command 112 sent from the central power dispatch center 101, and calculates the amount of generator output adjustment for the entire power plant in advance in the DPC command redistribution section 205. AFC distribution rate 211 of each unit calculated using the command redistribution means
is used to calculate the generator output adjustment amount 212 by AFC of each unit and send it to each unit.

When each unit receives its respective DPC command value 213,
D from the current output in the DPC pattern creation section 221
The PC command value 213 is adjusted to follow the operating pattern by recirculation flow rate control at the rate of change shown in FIG. 5 above. Further, when receiving the generator output adjustment amount 212 due to AFC of each unit, it is sent to the adding section 222 and added to the generator output request value 231 based on the operation pattern, and sent to the load setting device 223 to start the AFC operation. implement. When the generator output of each unit is changed to the respective DPC command value according to this operation pattern, the DP of each unit
The C operating range calculation unit 224 uses the DPC operating range calculation means to calculate a PC operating range 232 in which the output can be further adjusted from the changed core state.

This DPC operating range calculation means uses the existing core performance prediction function of each unit to predict an operating range that does not violate operating constraints.

In the high-speed operation range calculation unit 225, the high-speed operation range calculation means selects an operation range 233 within the above-mentioned DPC operation range 232 in which high-speed output change is possible below the output p1 shown in FIG.
Calculate.

The AFC operating range calculating section 226 calculates the AFC operating range allowed at each output within the operating range of the DPC using the AFC operating range calculation unit to determine the relationship 234 between the base output and the AFC operating range. AFC operation width prediction means Predicts the core state at several operating points within the DPC operation range using the existing prediction function in each unit, and predicts the state of the core when AFC operation at the maximum width is performed at each operating point. The amount of fluctuation in the core state is calculated using the formula described later, and this is added to the above prediction result to check whether the operating range will be exceeded.

Change ΔX in core state quantity i due to AFC operation can be expressed as Δχ■f (p, w, a) as reactor power p, core flow ff1w, and AFC operation interval number. The functional form of f shall be determined in advance so as to reproduce as much as possible the results of offline calculation using a detailed model.

As a result of the above-mentioned check, if it is determined that the operating range is exceeded, an AFC operating width that falls within the operating range is calculated. An example of the relationship 234 between the base output and the AFC operation width calculated in this way is shown in FIG.

The DPC operating range 232 calculated for each unit,
The high-speed operation range 233 and the relationship 234 between base output and AFC operation width are sent to the DPC command redistribution unit 205.

In the DPC command redistribution unit 205, the above-mentioned DPC operation range 232 and high-speed operation range 233 sent from each unit
From the relationship 234 between base output and AFC operation width, DP
Using the C command redistribution means, the central power dispatch center 101
High-speed operation capacity 113 required for the power plant from
, AFC operating capacity ff1114 and GF operating capacity ff11
Check whether 1 etc. are secured. If this is not satisfied, the standard output of each unit, that is, the DPC command, is redistributed so as to satisfy the required amount as much as possible.

Below, the DPC command redistribution means of this embodiment will be explained in detail using the flowchart of FIG.

In the data manual, high-speed operation capacity Jli 1113, AFC operation capacity 2 114 and GF operation capacity E1115 requested from the central power dispatch center 101, DPC operation range 232, high-speed operation range 233, relationship between base output and AFC operation width 234
301), first check whether the GF operation capacity is secured (302), and if it is determined that it is not secured, consider adding the number of units capable of CF operation (303). That is, since GF operation is possible when the generator output of the uni-node is lower than the output p2 shown in FIG. 7, the required number of units with higher outputs are set lower than the output p2.

In addition, in order to compensate for the output decrease due to this, the output p2
It is assumed that the output of the lower unit is increased within a range not exceeding p2.

If it is determined that if the output of the necessary number of units to secure the GF operating capacity is reduced to the output p2, the total power generation amount of the power plant will be lower than the DPC command, -(304), Calculate the possible GF operation capacity jii235 within the range that can secure the generator output of the DPC command and notify it to the central power dispatch center, and also calculate the generator output of each unit when obtaining the maximum possible GF operation capacity 235. The optimum PC command 236 of the unit is sent to the Dpc pattern creation section 221 of each unit.

In addition, calculate the AFC capacity of each unit when the optimum PC command 236 obtained here is used as the reference output, and add this to the AFC of the power plant at that time: E#ff
1237 to notify the central power dispatch center 101. There is also a possibility that the AFC capacity will not satisfy the amount requested from the central power dispatch center 101.

If the required GF capacity can be secured in the above, then calculate the AFC capacity of each unit when the DPC command after reallocation is used as the standard output, and add this to the central power dispatch center 101. It is checked whether the AFC capacity requested by the user is satisfied (305). As a result, if it is determined that the necessary AFC capacity cannot be secured, redistribution of DPC commands is considered again (306). Since the AFC capacity of the units whose operating points are at number 11 in FIG. 6 is limited, the operating points of these units are set to A.
In order to move the FC width in the direction of expansion and to compensate for the variation in generator output caused by this, the operating points of the units in the operating region 13 where the maximum AFC operating width is possible in Fig. 6 are set to the same reference numerals. The change shall be made within the operating range of 13.

In this way, the reference output of each unit, that is, the DPC command for each unit, is redistributed so that the required AFC capacity can be secured within the range that satisfies the DPC command and GF request amount. If it is determined that the necessary AFC capacity cannot be secured within the range that satisfies the DPC command and GF request amount (307), the maximum possible AFC capacity ff1237 is calculated and notified to the central power dispatch center 101, and the maximum The generator output of each unit when obtaining a possible AFC value is sent to the DPC pattern creation section 221 of each unit as the optimum PC command 236 of each unit.

In the above, G requested from the central power dispatch center 101
If both F capacity and AFC capacity are secured,
Next, calculate the high-speed operation width of each unit in the generator output after redistribution and check whether the high-speed operation capacity satisfies the amount requested from the central power dispatch center 101.'308)
, if not satisfied, the DPC commands of each unit are redistributed so that the necessary high-speed operation capacity can be secured after securing the above-mentioned GF capacity and AFC capacity (309).

As a means of expanding the high-speed operation capacity, among the units whose output is higher than PL and the units whose output is lower than PL in Fig. 5, the outputs are increased in order from the units with the smallest output change speed, as shown in Fig. 5. This becomes possible by further reducing the output of a unit that is lower than the output p1 of , and has a high output change speed. As an example, in a nuclear power plant with three units, the rated output of each unit is all 10,100 O, and the current output is all 800 MW.
If the output p1 in Fig. 5 is all 900 MW, the high-speed operation capacity will be 300 Mν, whereas,
-The unit output of the machine is 10100O, and the total power generation is 24
Each other unit output is set to 70 to ensure 00Mν.
If it is set to 0Mν, the high-speed operation capacity will be 400MW, which is 100MW more than before.

When the high-speed operation capacity ff1113, AFC operation capacity 114, and CF operation capacity 115 requested by the central power dispatch center 101 are secured by the above means, the output of each unit is reduced in step 311 within the range that each of the above-mentioned operation capacities can be secured. The DPC commands 236 are redistributed so as to be as even as possible. This is because if the DPC operation is performed using as many units as possible, the amount of change in the generator output per unit time of the power plant, that is, the rate of change in the output becomes larger, so that the target output can be reached more quickly.

Finally, after the DPC command is optimally redistributed to each unit by the above-mentioned means, the DP
As a distribution method to each unit when a C command or an AFC command is received, the DPC distribution rate and AFC distribution rate to each unit are given as the ratio of the respective capacity of each unit to the respective capacity of the entire power plant ( 312). As a result, all units can perform output control in parallel according to their respective capacities in response to commands from the central power supply control center 101.

[Effects of the Invention] As explained above, according to the load following operation device for a nuclear power plant of the present invention, instead of individually sending the DPC command and AFC command from the central power dispatch center to each unit in the power plant, The DPC command for the entire power plant shall be sent from the central power dispatch center, and during AFC operation, the amount of generator output adjustment for the entire power plant will be calculated from the AFC command, and these requested amounts will be appropriately distributed to each unit within the power plant. By doing so, it will be possible to maximize the load following operation capability of the power plant, and the contribution to the economic efficiency and stability of system operation will be greatly increased.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an embodiment of the load following operation device for a nuclear power plant of the present invention, FIG. 2 is a diagram showing the relationship between the AFC operating width and base output of the AFC operating width calculation means of the embodiment, and The figure is a flowchart showing the processing flow of the DPC command redistribution means of the embodiment, Figure 4 is a diagram showing the operating range of the nuclear power generation unit as the relationship between generator output and core flow rate, and Figure 5 is the generator output Figure 6 shows the relationship between rising speed and generator output. Figure 6 shows the operating range where the maximum AFC operation width is possible. Figure 7
The figure shows an operating range in which GF operation is possible. 101... Central power dispatch center 01...
...DPC command input section 02...A
FC command input section 03...Unit) DPC
Command creation section 04...Unit AFC command creation section 05...DPC command redistribution section 21
......DPC pattern creation section 24...
...DPC operating range calculation section 25...
・High-speed operation range calculation unit 26...AFC operation range calculation unit Applicants: Japan Atomic Energy Corporation Toshiba Corporation

Claims (1)

[Scope of Claim] A load following operation device for a nuclear power plant equipped with a plurality of power generation units, comprising: a load follow operation range calculation means for calculating a load follow operation range based on the operating state of each of the power generation units; a high-speed operation range calculation means for calculating a high-speed operation range in which the output can be changed at high speed within the calculated load-following operation range; and an adjustment for calculating an adjustable output operation range that is allowable for each output within the load-following operation range. An output operation width calculation means, and a load following operation command value of each power generation unit is redistributed so as to secure the high speed operation capacity, adjusted output operation capacity and governor free operation capacity required in advance for the nuclear power plant, and the load The load following operation distribution rate and adjusted output distribution rate for appropriately distributing the following operation command and adjusted output command to each power generation unit are determined by the load following operation capacity and adjusted output operation of each generation unit after the load following operation command is redistributed above. A load following operation device for a nuclear power plant, comprising a load following operation command redistribution means that calculates based on capacity.