JPS6278405A - Control device for power system - Google Patents

Abstract

PURPOSE:To enable control for minimizing a total energy cost in a power system wherein a turbine and a motor are selectively operable, by evaluating a cost change in the change of operation mode. CONSTITUTION:Steam generated in each boiler 1A and 1B actuates each medium-pressure turbine 4A and 4B for driving each pump 6A and 6B via a power generating back-pressure turbine 2 for driving a generator 3, and returns to a condenser 8. Also, each pump 7A and 7B as driven by corresponding motors 5A and 5B are installed in parallel for each pump 6A and 6B. In this case, each kind of information I is taken into a process data input device 12 and operated on a control operation device 13. ANd through a plant control panel 14, each kind of information I is made to correspond to optimization for cost reduction and fed out, thereby controlling each machine and equipment.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a power system control device, and in particular, a function for calculating the cost of steam in a power system in which a steam turbine and a motor can be selected for driving a load. The present invention relates to a power system control device suitable for economical operation.

[Technical front of invention]

In private thermal power generation equipment, high-temperature, high-pressure steam generated in a boiler may be used in a back-pressure turbine for power generation, and then used as motive power in a medium-low pressure steam turbine. in this case,
A power system is used in which another power source such as a motor is installed so that it can be used selectively with the medium and low pressure turbine. In such a system, power costs vary depending on the equipment driving the load, but it goes without saying that lower total energy costs are desirable.

On the other hand, in controlling a turbine/boiler system, the steam flow must be balanced at each pressure level. For this reason, in the private thermal power generation equipment described above, first the operation/stop of the medium and low pressure turbine is determined, and then the main steam temperature of the back pressure turbine for power generation and the main steam of the boiler are determined by considering the steam balance. A method is used. However, in equipment using such a control method, it is difficult to determine whether to start or stop the medium-low pressure turbine in a way that minimizes the total energy cost. However, although this decision is made according to norms based on experience or general prior evaluation, it is difficult to optimize power cost reduction because it does not adequately respond to changes in conditions such as load fluctuations. There are problems.

In response to this, in recent years, control devices have come into use that optimally operate private thermal power generation equipment by creating mathematical models of steam and electrical equipment and applying mathematical programming. However, such a control system not only requires a detailed mathematical model of the entire equipment, but also requires a considerable amount of time for calculations. It has the disadvantage that it is not necessarily suitable for the purpose of reduction optimization.

[Purpose of the invention]

Therefore, an object of the present invention is to solve the problems of the prior art described above, and to reduce the cost of steam used in the medium and low pressure turbine in a power system that can selectively use a medium and low pressure turbine and other power sources. : By calculating from 1st 1- and the cost i of externally received power reduced by power generation,
An object of the present invention is to provide a power system control device that makes on/off decisions such that total energy costs are reduced.

[Summary of the invention]

In order to achieve the above object, the present invention can select and use a turbine driven by medium and low pressure steam from a turbine generator device and a motor driven by electric power from the turbine generator equipment and purchased electric power. In the power system that can be used, the required steam level is determined when the operation mode of the power system is turbine drive and motor drive. Calculating means for calculating the steam cost obtained by summing up the cost of fuel consumed in the boiler for generation for each operation mode of the power system, and the steam cost and motor drive in the case of turbine drive obtained by this calculating means A power system control device comprising: comparison means for comparing the sum of steam cost and motor power when It provides:

[Embodiments of the invention]

Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 is a system diagram of a power system control m+ device according to an embodiment of the present invention. As shown in the figure, boilers IA, I
The steam generated in B passes through the back pressure turbine 2 for power generation to drive the generator 3, drives the medium and low pressure turbines 4A and 4B to drive the pumps 6A and 6B, and then to the condenser 8. leading to.

In addition, the pump 6 driven by the medium and low pressure turbines 4A and 4B
For △ and 6B, motor 5Δ.

Pumps 7A, 7B driven by pump 5B are placed in parallel in B2, and pumps 6A, 7A and pump 6B.

The outflow which is each load of 7B is flow meter 11A.
, 11B. On the other hand, where does the power system come from, where power is input from the power receiving end 9 from the power company through the circuit breaker 1o? The system from fifJ3 is also operated, and motor 5
It is configured to supply power to A and 5B. The control system applied to the above-mentioned system is composed of a process data input device 12, a control F>:r sieve device 13, and a plant control panel 14. , each boiler 1△, IB steam generation cans S, S, main steam ωB of power generation back pressure turbine 2
I B2 S, power generation date P of generator 3, from power receiving end 9・TG
I TGI electricity purchase ff1r'R
, each steam 51S11 of the medium and low pressure turbines 4Δ, 4B. S1
2. Input power PH1, PH2 of motors 5A, 5B, pump load detected by flow meters 1Δ, 11B,
L2 is input into the process data input device 12, and the control oil is controlled by 913. Low pressure turbine 4A, = steam ω of IB,
The electric power of the motors 5A and 5B is sent out in accordance with the optimization based on loss 1 to reduction, and each device is controlled.

The operation of this configuration will now be explained according to flowchart 1 in FIG.

In addition, in the explanation of the following operation, a case will be explained taking as an example a case in which the cos I to ratio axis is performed for the combination of the medium and low pressure turbine 4A and the motor M1. Incidentally, it is assumed that the medium and low pressure turbine 4A and the pump 6A are currently in operation. .

First, in step O◯, the system is initialized, and then in step 01, the current values of process data are read into the process data input device 12.

In the next step 02, the current pump drive mode is determined, and this is based on the steam flow ff1S11. From S12 and motor power P 1 , P 2 , the current drive mode of pump H1M2 is turbine 4A, 4B, motor 5Δ.

5B is determined for each combination.

In the next step 03, calculate the steam speed or motor power amount when changing the pump drive mode: t c':
i? However, in this case, the steam flow m511 and the motor power PH1 are determined as functions of the pump load L.

5Ti=fTi(Li) ・・・・・・・・・
(1)P)Ii=f)Ii(Li)...
...(2) In step 04, the medium and low pressure turbine 4
Main steam amount S of back pressure turbine 2 for power generation when A is stopped
1 Find the steam generation amount SB1°TGl S82 of boiler △, IB.

Now, if you change the pump drive mode, the main steam" 5
TG1 is S11 [decreased from the current situation. In addition, the steam generation ff1s81 of each boiler A, 1B and the water content of S, 2 are similarly reduced. At this time, the distribution of the reduction in the steam generation amount of boiler Δ, 1B is made proportional to ((current flow rate), -(lower limit value) i).

In the next step 05, the steam cost when the medium and low pressure turbine 4A is stopped is calculated.

Now, the steam cost in this case can be calculated using the following formula.

(Steam cost) = 2 - (power generation ff1P) - (unit price of electricity)...
(3) TGl Meanwhile, boiler fuel Qi 1. is steam generationff1S6.
is a function of

○i l, = f eH (S H)...
・・・・・・(4)■ Also, power generation station P engineering. 1 is the main steam volume S. It is a function of 1.

P=f(S)...
...(5) TGI TGI TGl In the next step 06, the current steam cost is subtracted. This is calculated by using equation (3) from the current fuel consumption and power generation 1.
Count by 1.

In step 07, when driving the pumps 6A and 7A, loss 1 between turbine drive and motor drive - comparison and hot air cost when turbine drive is selected - and steam cost and motor consumption when motor drive is selected Electric power PH
Compare the sums of 1 and select the lower mode.

When the current drive mode and the drive mode selected by calculation are different, control is performed in step 08 to switch the drive mode.

Each of the above steps 01 to 08 is repeatedly performed with a fixed delay time determined in step 09.

As mentioned above, when determining the drive mode of the pumps 6A and 7Δ, the difference between fuel and fuel consumption is determined based on the change in steam flow rate. Since the cost I-change in the amount of t2 is calculated and compared, operation can be performed with less total energy cost.

Note that the operation mode control υ11 based on comparison can be similarly applied to the case where a plurality of back pressure turbines for power generation are installed in parallel.

Also, two turbines 4Δ, 4 are connected to one motor 5.
H as shown in the system diagram in Figure 3 where B is installed in parallel.
Even in H65, costs can be reduced by comparing the drive mode by Ko-Yu 5 and the energy cost 1- for the case where only one turbine 4A or 4B is operated and the case where turbines 4A and 4B are operated in parallel. It is possible to implement optimization control for the

〔Effect of the invention〕

As described above, according to the present invention, the total energy cost is minimized by evaluating the cost change when changing the operation mode in a dynamic horn system that can be used by selecting a turbine and a motor. It is possible to obtain a power system control device that enables control such as.

[Brief explanation of drawings]

Fig. 1 is a system diagram of a power system control device according to an embodiment of the present invention, Fig. 2 is a flowchart t7- showing an outline of control leakage calculation of the device of Fig. 1, and Fig. 3 is an application of the present invention. FIG. 11 is a system 11 diagram showing another possible system example. 1△, 1B... Boiler, 2... Back pressure turbine for power generation, 3... Generator, 4A, 4B... Medium and low pressure turbine,
5△. 5B, 5...Motor, 6A, 6B, 7Δ, 7B...
Pump, 12... Between process data input stations, 13...
・Control oil p neck, 14...Plant control panel. Applicant's Representative Fi Embryo - Interest α No. 1
ano 2 Figure 3

Claims (1)

[Claims] In a power system that can selectively use a turbine driven by medium and low pressure steam from a turbine generator device and a motor driven by electric power from the turbine generator device and purchased electric power, an operation mode of the power system. Calculate the amount of steam required for the cases where is driven by a turbine and when it is driven by a motor, and calculate the reduction in purchased electricity cost reduced by the output of the turbine generator device and the fuel consumed by the boiler to generate steam. A calculating means for calculating the steam cost obtained by summing the costs for each operation mode of the power system, and calculating the steam cost for turbine drive, the steam cost for motor drive, and the motor power obtained by this calculating means. A power system control device comprising a comparison means for comparing the sums, and a switching means for switching the power system to an operation mode with lower energy cost based on the output of the comparison means.