JPS58164990A - Control device for air cooled condenser - Google Patents

Abstract

PURPOSE:To improve the following characteristic of the titled device to meet a sudden load change in a process having a constant bypass, by a method wherein the blade angle of each of cooling fans is operated to generate a feedforward signal, the ON- OFF amount of a fan number control system is analogized and the amount of operation of the device is varied precedently. CONSTITUTION:When a load changes suddenly, the change is detected as the amount of variation of a turbine inlet steam flow rate 16 and the amount of variation of a turbine bypass steam flow rate 17 before it is detected from the pressure 19 of a condenser. Then the change is operated by a feedforward signal operation section B and the result of operation is converted into the equivalent of the amount of operation of the blade angle control device to thereby increase or decrease the amount of operation directly. Further, with the variation of the load, a fresh target value operated by a final target value setting section A is adjusted finely by a pressure adjust meter D in consideration of the result of control. Thus, when the amount of operation reaches its upper or lower limit, the cooling fans 21 are started or stopped in sequence by the operation of a cooling fan number precedence element introducing section C and at the same time, the amount of operation is increased or decreased directly as a correcting part of the feedforward signal by making the load change equivalent to the amount of operation for the change in the fan number, as a precedence element.

Description

[Detailed description of the invention] The present invention relates to a control device for an air-cooled condenser.

Conventional control of air-cooled condensers, for example, as shown in the system diagram in Figure 1, is mainly a combination of cooling fan blade angle control through simple pressure adjustment and manual control of the number of cooling fan drives based on the load. As shown in the figure, a method is known in which exhaust air humidity is ensured by causing a pressure adjustment setting section to generate a function. In Fig. 1, 01 is the turbine input-steam flow rate, 02 is the polygonal line approximator, 03 is the setting device, 04 is the condenser pressure, 05 is the controller, 06 is the automatic-manual operator, and 07
is a cooling fan blade angle control device.

However, such a control method has a problem in that sufficient load follow-up characteristics cannot be obtained during sudden load changes. Therefore, in processes where air-cooled condensers are often used as condensers in power generation equipment attached to incinerators and have a constant bypass, the characteristics against sudden changes in load may be affected. Improvement is desired.

The present invention has been proposed in view of the above circumstances, and is an air-cooled condenser control system that improves the follow-up characteristics in response to sudden changes in load in steam power generation plants that use air-cooled condensers and processes that have a constant bypass. In an air-cooled condenser equipped with a plurality of cooling fans, cooling based on the approximate thermal calculation of the system including an outside temperature element;
a feedforward signal calculation section that calculates the H angle of y and outputs it as a feedforward signal, and a leading g collection introduction section that analogizes the on/off amount of the cooling fan number control system and thereby changes the manipulated variable in advance. It is characterized by having the following.

An embodiment in which the present invention is applied to a turbine power generation plant will be described with reference to the drawings. FIG. 2 is a system diagram thereof, and FIG. 3 is a block diagram showing the control system of FIG. 2.

In the above figure, 1 is a broken line approximator f(xt), 2 is a ratio setter X13 is an adder Σ, 4 is a function generator f(t), 5 is an upper and lower limit limiter, 6 is a divider ÷, is a lower limit alarm setter with hysteresis, 8 is an upper limit alarm setter with hysteresis, and 9 and 10 are function generators f(xt), respectively.
and f(xs), 11 is adder +, 12 is adder Σ
, 13 is an automatic/manual operation device, 14 is a cooling fan true angle control device, 15 is an outside air temperature, 16 is a turbine inlet steam current,
17 is a turbine bypass steam flow rate, 18 is a setting device, 1
9 is the condenser pressure, 2o is the air-cooled condenser heat transfer area, 21 is the condenser cooling fan, 22 is the condenser cooling fan drive motor,
23 is a turbine, 24 is a generator, 25 is a regulator, 26 is a controller, and 27 (-i control system).

The control device according to the embodiment of the present invention is composed of the following four main parts A, B, C, and D, as shown in FIG.

A...Final target value setting unit determined by turbine characteristics such as exhaust temperature, B...Feedforward signal calculation unit based on bold approximation calculation of process heat balance, cooling/cooling by θ oc KQ −L Approximate calculation of fan blade angle θ (operated amount)□
Ru. Here, Ql is the total amount of heat input (enthalpy base) of the air-cooled water tank heat transfer 'rkJ product 20, and □·t is the outside air temperature.

C... Introducing the preceding element into the manipulated variable of the cooling fan) 22, P...-Pressure regulator section, In such a device, when there is a sudden load change, this change is caused by the condenser pressure 19, the change in the turbine inlet steam flow Mk16 and the turbine bypass steam flow t17 is equivalently converted into a manipulated variable of the control device, and the manipulated variable is directly adjusted as a feedforward signal.

As the load changes, the new target value calculated by the final target value setting section A is finely adjusted by the pressure adjustment needle based on the control result of the feedforward signal calculation section B.

When the above operation 1 reaches the upper limit or lower limit, the cooling fan number advance element introduction part C starts and stops the cooling fans 21 one by one, and precedes the change in operation amount corresponding to the change in the number of fans. The final target value can be obtained with high accuracy by directly increasing or decreasing the manipulated variable as an element other than the correction of the feedforward signal, and by using the pressure regulator.

According to a device like Jin, the following effects can be achieved.

(1) Stable and good control results and load followability can be obtained in all situations, including during sudden load changes (by the feedforward effect).

(2) Even in the case of controlling the number of cooling fans at the operation end, which is a disturbance generating factor in the own system, the operation amount can be changed to the advance stability region by converting the on/off amount to the analog pg amount.

(3) The above can be easily constructed by combining general-purpose equipment.

In short, according to the present invention, in an air-cooled condenser equipped with a plurality of cooling fans, the blade angle of the cooling fan is calculated based on the approximate thermal calculation amount of the system including the outside air temperature element, and this is output as a feedforward signal. Load followability is improved by providing a "feedforward signal calculation section" that converts the on/off amount of the cooling fan number control system into analog, and a preceding element introduction section that changes the operation amount in advance. The present invention is extremely useful industrially because it provides a good control device for an air-cooled condenser.

[Brief explanation of drawings]

#! 1 is a control system diagram of a known air-cooled condenser, FIG. 2 is a system diagram showing an embodiment of the present invention, and FIG. 3 is a block diagram showing the control system of FIG. 2. 1... Broken line approximator, 2... Ratio setter, 3... Adder, 4... Function generator, 5... Upper and lower limit limiter, 6
... Divider, 7... Lower limit alarm setter with hysteresis, 8... Upper limit alarm setter with hysteresis, 9.10... Function generator, JJ, 12... Adder, 13... Automatic-manual operation device, 14... Cooling fan blade angle control device, 15... Outside air temperature, 16... Turbine inlet steam flow rate, 17... Turbine bypass steam flow rate, 18... Setting device, 19... Condenser pressure, 20...
・Air-cooled condenser heat transfer area, 21... Condenser cooling fan false 22... Condenser cooling fan drive motor, □ 23... Turbine, 24... Generator, 25... Adjustment device, 26,...controller, 27..., leg restraint system2. Tem〇Applicant Sub-Agent Patent Attorney Takehiko Suzue
7- Figure 1

Claims (1)

[Claims] In an air-cooled condenser equipped with multiple cooling fans, a feedforward signal that calculates the fan angle based on the approximate thermal calculation amount of the system including the outside air temperature element and outputs this as a feedforward Ig@. 1. A control device for an air-cooled condenser, comprising: a calculation section; and a preceding element introducing section that analogizes the on/off control of a cooling fan number control system and changes the operation amount in advance.