CN-122015521-A - Regional operation and backpressure safety control method for condenser

CN122015521ACN 122015521 ACN122015521 ACN 122015521ACN-122015521-A

Abstract

The invention relates to the technical field of thermodynamic systems of power plants, and provides a regional operation and backpressure safety control method of a condenser, which comprises the steps of firstly dividing a circulating water system of the condenser into two independent controllable regions, controlling the on-off of circulating water of each region by an independent valve, then monitoring the operation parameters of a unit in real time, including the load of a turbine, the temperature of an inlet of the circulating water and the backpressure of the condenser, and then setting a back pressure-load-water temperature relation model based on the operation parameters monitored in the step two, dynamically deciding and selecting the current optimal regional operation mode of the condenser, finally executing the switching operation of the regional operation mode after the preset safety interlocking condition is met according to the decision result, and controlling the back pressure of the condenser within a target range by adjusting the working state of the circulating water system in the whole process. According to the invention, through the partition operation, only part of the cooling area is put into the proper working condition, so that the power consumption required by driving the circulating water pump can be obviously reduced.

Inventors

HAN XU
CHENG HAOLUN
WANG XIANG
LI DONGDONG
ZHENG TIANQUAN
WANG RONGFENG
LV HAIPENG
WANG XINDING
JI PENGFEI
LIN CHUNJI
JIANG PENG
GUO TAO
GONG ZILIANG
CONG SHULIN
SAI BEI
ZHANG JUNQIAO
CONG SHUGUANG
GUO HAO
LI MANGMANG
Ai Fangxing
SHEN ZHAOLIANG
CHEN ZHU

Assignees

华能国际电力股份有限公司大连电厂

Dates

Publication Date: 20260512
Application Date: 20260317

Claims (10)

1. The regional operation and backpressure safety control method for the condenser is characterized by comprising the following steps of: dividing a circulating water system (20) of a condenser (10) into two independent controllable areas, wherein each area is provided with an independent valve for controlling the on-off of circulating water; Monitoring operation parameters of the unit in real time, including turbine load, circulating water inlet temperature and condenser back pressure; Step three, mode decision, namely setting a back pressure-load-water temperature relation model based on the operation parameters monitored in the step two, dynamically deciding and selecting the current optimal regional operation mode of the condenser; And step four, safety switching and control, namely executing switching operation of the partition operation mode after the preset safety interlocking condition is met according to the decision result of the step three, and controlling the back pressure of the condenser within a target range by adjusting the working state of the circulating water system in the whole process.
2. The method for safely controlling the operation and the back pressure of the condenser in a partitioning manner according to claim 1, wherein the circulating water system (20) comprises a water tank (201), the inner part of the water tank (201) is divided into an area A water storage cavity (202) and an area B water storage cavity (203), the inlet end of the area A water storage cavity (202) is fixedly connected with a first water inlet pipe (204), the first water inlet pipe (204) is fixedly connected with a first water inlet valve (205), the inlet end of the area B water storage cavity (203) is fixedly connected with a second water inlet pipe (206), the second water inlet pipe (206) is fixedly connected with a second water inlet valve (207), the outlet end of the area A water storage cavity (202) is fixedly connected with a first water outlet pipe (200), the first water outlet pipe (200) is fixedly connected with a first water outlet valve (20 a), the outlet end of the area B water storage cavity (203) is fixedly connected with a second water outlet pipe (20B), the second water outlet valve (20 c) is fixedly connected with a second water outlet pipe (206), the inlet end of the first water inlet pipe (206) is fixedly connected with a main pipe (20B), the main water outlet pipe (20 d) is fixedly connected with a main water outlet valve (20 e).
3. The method for safely controlling the operation and the back pressure of the condenser in a partitioned mode according to claim 2, wherein the first water inlet valve (205), the second water inlet valve (207), the water inlet main valve (209), the first water outlet valve (20 a), the second water outlet valve (20 c) and the water outlet main valve (20 e) are all electromagnetic valves.
4. The method for safely controlling the operation and the back pressure of the condenser in a partitioned mode according to claim 3, wherein in the second step, the load of the steam turbine is directly calculated by measuring the output electric power of the generator by the transmitter, and the specific monitoring process is as follows: a1, a transmitter acquires three-phase voltage and three-phase current signals of an outlet of a generator in real time through a voltage transformer and a current transformer; a2, calculating signals by a circuit based on a microprocessor in the transmitter to obtain active power, wherein the calculation formula is as follows: P= v3 x V x I x cos phi, where V is the line voltage, I is the line current, cos phi is the power factor; A3, the transmitter converts the calculated power value into a standard analog quantity signal, and the standard signal is transmitted to an analog quantity input module of the distributed control system through a shielded cable; And A4, filtering the received signals by the DCS to eliminate high-frequency interference, performing range conversion, correspondingly converting the 4-20mA signals into rated power, displaying the load value on a picture in real time, and taking the load value as a key input point of control logic.
5. The method for safely controlling the operation and the back pressure of the condenser partition according to claim 3, wherein in the second step, the specific monitoring process of the inlet temperature of the circulating water is as follows: B1, installing a temperature sensor on a pipe section with stable water flow of a water inlet main pipe (208), wherein a temperature measuring sleeve is adopted in an installation mode; B2, the temperature sensor senses the temperature of the circulating water, and the resistance value is changed along with the temperature sensor; b3, the resistance signal is connected to a temperature transmitter in the DCS cabinet through a three-wire system or four-wire system connection method; The temperature transmitter converts the weak resistance change signal into a standard 4-20 mA DC signal corresponding to a temperature range, and sends the standard signal into the DCS; and B5, performing signal acquisition and linearization processing on the DCS, and converting the current value into an actual temperature value.
6. The method for safely controlling the operation and the back pressure of the condenser in a partition manner according to claim 3, wherein in the second step, the specific monitoring process of the back pressure of the condenser is as follows: c1, leading out an absolute pressure transmitter from a measuring point of a steam space of a condenser through a pressure guide pipe, and installing a condensing tank at one end of the pressure guide pipe, which is close to the transmitter; The absolute pressure in the condenser is transmitted to a positive pressure side diaphragm of the pressure transmitter through a pressure guide pipe and a water column in the condensing tank, the negative pressure side of the transmitter is used as a sealed vacuum reference cavity, the diaphragm is slightly deformed by pressure difference, and a Wheatstone bridge on the diaphragm outputs an electric signal; And C3, amplifying and linearizing the signal by a circuit in the transmitter, outputting a 4-20 mA DC signal proportional to absolute pressure, and then sending the signal into the DCS, wherein the DCS converts the current signal into a pressure value.
7. The method for controlling the partition operation and the back pressure safety of a condenser according to claim 5, wherein in the third step, the operation modes of the back pressure-load-water temperature relation model include a full-throw mode and a single-zone operation mode; the full throw mode is that the first water inlet valve (205), the second water inlet valve (207), the water inlet main valve (209), the first water outlet valve (20 a), the second water outlet valve (20 c) and the water outlet main valve (20 e) are all opened, at the moment, the cooling area is the largest, the heat exchange capacity is the strongest, and the full throw mode is suitable for high heat load or high temperature seasons so as to maintain lower back pressure; In the single-zone operation mode, the first water inlet valve (205), the first water outlet valve (20 a) or the second water inlet valve (207) and the second water outlet valve (20 c) are opened, and circulating water only flows through the water storage cavity (202) in the zone A or the water storage cavity (203) in the zone B.
8. The method for safely controlling the operation and the back pressure of the subarea of the condenser according to claim 3, wherein the decision logic of the back pressure-load-water temperature relation model comprises: when the unit load is lower than a first preset threshold value and the circulating water temperature is lower than a second preset threshold value, deciding to be a non-full-throw mode of throwing the operation of the partial area; when the unit load is higher than a third preset threshold value or the circulating water temperature is higher than a fourth preset threshold value, the unit load is decided to be in a full-throw mode of running in all areas.
9. The method according to claim 8, wherein in the third step, the back pressure-load-water temperature relation model further introduces the supercooling degree of the condensed water as an auxiliary decision parameter, and when the supercooling degree is detected to exceed the safety limit, the partition operation mode is forcibly switched or the circulating water flow is adjusted to eliminate the supercooling.
10. The method for safely controlling the operation and the back pressure of the condenser partition according to claim 9, wherein the safety interlock condition comprises: Mode switching locking, namely when the back pressure of the real-time condenser is higher than a first safety limit value, locking any operation of switching from a full-throw mode to a non-full-throw mode by the system; Sequential control interlocking, wherein when the mode switching is executed, the control system follows sequential logic of opening the target mode access valve firstly and closing the original mode access valve later to prevent the interruption of circulating water; And (3) emergency protection, namely triggering an emergency tripping signal of the unit and forcedly switching the condenser to a full-throw mode when the back pressure of the real-time condenser is higher than a second higher safety limit value.

Description

Regional operation and backpressure safety control method for condenser Technical Field The invention relates to the technical field of thermodynamic systems of power plants, in particular to a regional operation and backpressure safety control method of a condenser. Background The condenser is a key auxiliary device of a turbo generator set, and mainly has the function of condensing the spent steam discharged by the steam turbine into water, so that high vacuum (low back pressure) is established and maintained at the steam discharge end of the steam turbine, the back pressure (namely steam side pressure) of the condenser is a core parameter for measuring the performance of the condenser, the economical efficiency and the safety of the set are decisively influenced, and a circulating water system is required to provide cooling in order to maintain the optimal back pressure. The circulating water pump drives cooling water (usually river water or seawater) to flow through thousands of titanium pipes or stainless steel pipes in the condenser to take away condensation heat of steam outside the pipes, and the circulating water pump is one of main power consumption equipment in the power plant, and the power consumption (namely 'station electricity') directly influences the net output power and the operation cost of the power plant; In the conventional or conventional condenser operation mode, the following defects mainly exist: First, the prior art generally employs a "full throw mode" of operation, i.e., the circulating water system is always operating at maximum capacity (full cooling area input) regardless of turbine load level, season (ambient water temperature) changes. In the working condition, the operation of maintaining the whole cooling area belongs to 'overcooling', so that the operation is unnecessary, a large amount of electric energy of a circulating water pump can be consumed, the plant power consumption is high, the energy waste is caused, and the overall operation economy of the power plant is reduced; Second, conventional backpressure control relies mostly on operator experience or simple constant value control, such as adjusting the total circulating water volume by adjusting the number of operating cycles or rotational speed of the circulating water pump, which lacks accurate modeling and real-time optimization of the dynamic relationship between "load-water temperature-backpressure". Disclosure of Invention The invention provides a method for safely controlling regional operation and back pressure of a condenser, which solves the problem of electric energy waste caused by full-throw mode operation in the related technology. The technical scheme of the invention is as follows, the method for safely controlling the regional operation and the back pressure of the condenser comprises the following steps: Dividing a circulating water system of a condenser into two independent controllable areas, wherein each area is provided with an independent valve for controlling the on-off of circulating water; Monitoring operation parameters of the unit in real time, including turbine load, circulating water inlet temperature and condenser back pressure; Step three, mode decision, namely setting a back pressure-load-water temperature relation model based on the operation parameters monitored in the step two, dynamically deciding and selecting the current optimal regional operation mode of the condenser; And step four, safety switching and control, namely executing switching operation of the partition operation mode after the preset safety interlocking condition is met according to the decision result of the step three, and controlling the back pressure of the condenser within a target range by adjusting the working state of the circulating water system in the whole process. Preferably, the circulating water system comprises a water tank, the interior of the water tank is divided into an area A water storage cavity and an area B water storage cavity, the inlet end of the area A water storage cavity is fixedly connected with a first water inlet pipe, the first water inlet pipe is fixedly connected with a first water inlet valve, the inlet end of the area B water storage cavity is fixedly connected with a second water inlet pipe, the second water inlet pipe is fixedly connected with a second water inlet valve, the outlet end of the area A water storage cavity is fixedly connected with a first water outlet pipe, the first water outlet pipe is fixedly connected with a first water outlet valve, the outlet end of the area B water storage cavity is fixedly connected with a second water outlet pipe, the second water outlet pipe is fixedly connected with a second water outlet valve, the inlet ends of the first water inlet pipe and the second water inlet pipe are fixedly connected with a water inlet main pipe, the outlet ends of the first water outlet pipe and the second water outlet pipe are fixedly connected with a w