CN115182794A - Method for reducing disturbance of two loops of power plant during grid connection - Google Patents
Method for reducing disturbance of two loops of power plant during grid connection Download PDFInfo
- Publication number
- CN115182794A CN115182794A CN202110363505.4A CN202110363505A CN115182794A CN 115182794 A CN115182794 A CN 115182794A CN 202110363505 A CN202110363505 A CN 202110363505A CN 115182794 A CN115182794 A CN 115182794A
- Authority
- CN
- China
- Prior art keywords
- grid connection
- state
- disturbance
- reducing
- grid
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000000034 method Methods 0.000 title claims abstract description 37
- 239000007788 liquid Substances 0.000 abstract description 9
- 230000001105 regulatory effect Effects 0.000 abstract description 6
- 230000000694 effects Effects 0.000 abstract description 3
- 230000009286 beneficial effect Effects 0.000 abstract description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 6
- 230000008016 vaporization Effects 0.000 description 2
- 238000009834 vaporization Methods 0.000 description 2
- 230000002401 inhibitory effect Effects 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
Images
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
- F01D21/00—Shutting-down of machines or engines, e.g. in emergency; Regulating, controlling, or safety means not otherwise provided for
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
- F01D17/00—Regulating or controlling by varying flow
- F01D17/10—Final actuators
- F01D17/105—Final actuators by passing part of the fluid
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
- F01D21/00—Shutting-down of machines or engines, e.g. in emergency; Regulating, controlling, or safety means not otherwise provided for
- F01D21/003—Arrangements for testing or measuring
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
- H02J3/381—Dispersed generators
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J2300/00—Systems for supplying or distributing electric power characterised by decentralized, dispersed, or local generation
- H02J2300/20—The dispersed energy generation being of renewable origin
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Control Of Turbines (AREA)
Abstract
The invention aims to provide a method for reducing the disturbance of a secondary loop of a power plant during grid connection, which is characterized in that a bypass valve is synchronously closed during grid connection, so that the effect of large hedging with a steam turbine regulating valve is achieved, the disturbance of the grid connection to the pressure and the liquid level of an evaporator is reduced, and the purpose of reducing the disturbance of the secondary loop is finally achieved. The method comprises the following steps: step 1: the method comprises the following steps of using the switching state of a generator outlet circuit breaker and the pressure of a turbine impulse stage as judgment conditions for judging whether a turbine is connected to the power grid or not; and 2, step: closing a bypass valve after judging that the steam turbine is successfully connected to the grid; and step 3: reset valves and logic. The beneficial effects are that: the method provides a feasible, practical and accurate control method, and the bypass valve is closed while the grid is connected, so that the disturbance of the opening of the adjusting valve on the pressure and the liquid level of the evaporator is reduced, and the purpose of reducing the disturbance of the two loops is finally achieved. Meanwhile, the method also considers some common false message failures or false signal phenomena so as to increase the reliability of the method and avoid misoperation.
Description
Technical Field
The invention belongs to the technical field of power station operation and maintenance, and particularly relates to a method for reducing disturbance of a secondary loop of a power plant during grid connection.
Background
Before the power plant is connected to the grid, only steam idling of a steam turbine needs to be maintained, and most of the steam is discharged into a condenser through a bypass valve; after the generator is connected to the grid and the initial load is applied, the regulating valve of the steam turbine needs to be opened quickly to increase the steam inlet quantity. This causes a large drop in evaporator pressure and the instantaneous vaporization of the high temperature water in the evaporator creates a false water level. This disturbance, being of large amplitude, presents great difficulties for the control of the two loops. The great disturbance of the two loops during the grid connection is a phenomenon existing in all power plants, even in some power plants, thereby causing the occurrence of events.
Disclosure of Invention
The invention aims to provide a method for reducing the disturbance of a secondary loop of a power plant during grid connection, which is characterized in that a bypass valve is synchronously closed during grid connection to achieve the effect of opening and colliding with a steam turbine regulating valve to reduce the disturbance of the grid connection to the pressure and the liquid level of an evaporator, and finally the purpose of reducing the disturbance of the secondary loop is achieved.
The technical scheme of the invention is as follows: a method for reducing disturbance of a secondary loop of a power plant during grid connection comprises the following steps:
step 1: the method comprises the following steps of using the switching state of a generator outlet circuit breaker and the pressure of a turbine impulse stage as judgment conditions for judging whether a turbine is connected to the power grid or not;
step 2: closing a bypass valve after judging that the turbine is successfully connected to the grid;
and step 3: reset valves and logic.
The circuit breaker has an opening state and a closing state, impulse stage pressure is low before grid connection and high after grid connection, and the circuit breaker state and impulse stage pressure signals are combined and used for judging the state of the steam turbine.
The state of the steam turbine is judged to be,
the impulse stage is low in pressure, and the circuit breaker is disconnected and is in a shutdown state.
The state of the steam turbine is judged to be,
the impulse stage pressure is high, and the breaker is disconnected and is in an impulse state.
The state of the steam turbine is judged to be,
the impulse stage pressure is high, the breaker is closed, and the circuit is in a grid-connected state.
The state of the steam turbine is judged to be,
after grid connection, the impulse stage pressure is kept high, the breaker is kept closed, and the grid connection is successful.
And 2, after the breaker is changed from the open state to the closed state, checking that the pressure of the impulse stage is higher than a fixed value, considering that the grid connection is successful, closing a bypass valve, and executing the step 3 if the pressure or the state of the breaker is changed and does not meet the condition of successful grid connection after the grid connection is successful.
And 3, when the grid connection is successful and the power is increased, the opening degrees of the two reset and opened bypass valves are calculated according to normal control logic.
The invention has the beneficial effects that: the method provides a set of feasible, practical and accurate control method, and the bypass valve is closed while the grid is connected, so that the disturbance of the pressure and the liquid level of the evaporator caused by opening of the regulating valve is reduced, and the purpose of reducing the disturbance of the two loops is finally achieved. Meanwhile, the method also considers some common false message failures or false signal phenomena so as to increase the reliability of the method and avoid misoperation.
Drawings
FIG. 1 is a comparison of evaporator liquid level fluctuation amplitudes after 205 overhaul grid connection (diamond-dotted line is 205 overhaul data);
FIG. 2 is a comparison of evaporator pressure fluctuation amplitudes after 205 overhaul grid connection (. Diamond-solid-dotted line 205 overhaul data).
Detailed Description
The invention is described in further detail below with reference to the figures and the embodiments.
After the generator is connected to the grid, the throttle of the steam turbine needs to be opened quickly, and the steam inlet quantity is increased to maintain the rotating speed of the generator. This causes a large drop in evaporator pressure and the instantaneous vaporization of the high temperature water in the evaporator creates a false water level. The two-loop control system closes the bypass valve and closes the main water supply valve according to the change of pressure and liquid level, so that the bypass valve and the main water supply valve are restored to the set values. This process will last for several minutes, during which the main steam flow, main feedwater injection, evaporator pressure and evaporator liquid level will all vary significantly, causing significant disturbances in the control of the entire two-circuit.
In the grid connection process, because the thermal power of the two loops is kept unchanged, after the whole two loops are stabilized, the opening of the regulating valve of the steam turbine and the closing of the by-pass valve are complemented, and after the two loops reach new balance, the flow of the main steam still keeps unchanged. The invention creatively advances the closing of the bypass valve to the grid connection and synchronizes with the opening of the regulating valve, thereby playing a role in hedging, inhibiting the fluctuation of the steam pressure and the flow in advance before the steam pressure and the flow change are actually generated, and reducing the large fluctuation process necessarily experienced by the original feedback control method.
The invention synchronously closes the bypass valve of the steam turbine after the unit is connected to the grid, thereby reducing the interference of the grid-connected operation on the pressure and the liquid level of the evaporator.
A method for reducing disturbance of a secondary loop of a power plant during grid connection comprises the following steps:
step 1: in the normal starting process, the state change of the steam turbine is as follows: shutdown → impulse → grid connection → success of grid connection. Using the on-off state of a generator outlet breaker and the pressure of a turbine impulse stage as judgment conditions for judging whether the turbine is connected with the power grid or not;
the circuit breaker has an opening state and a closing state, the impulse stage pressure is low before grid connection and high after grid connection, and the circuit breaker state and the impulse stage pressure signal are combined for judging the state of the steam turbine.
The impulse stage is low in pressure, and the breaker is disconnected and is in a shutdown state.
The impulse stage pressure is high, and the breaker is disconnected and is in an impulse state.
The impulse stage pressure is high, the breaker is closed, and the grid-connected state is realized.
After grid connection, the impulse stage pressure is kept high, the breaker is kept closed, and the grid connection is successful.
And 2, step: after the fact that the steam turbine is just connected to the grid successfully is judged, the bypass valve is quickly closed;
when the breaker is changed from an open state to a closed state, the pressure of the impulse stage is higher than a fixed value through checking, the grid connection is considered to be successful, and the bypass valve is closed quickly. And (4) if the conditions of successful grid connection are not met by the pressure or the state change of the breaker after the grid connection is successful, executing the step (3).
And step 3: resetting valves and logic.
When the grid connection is successful and the power is increased, the opening degrees of the two opened bypass valves (GCT 117VV and GCT121VV in the power plant) are reset and calculated according to normal control logic.
The method is realized by changing in the overhaul of 105 and 205 of the 1# unit of a certain power plant, and the 205 overhaul further optimizes the control parameters on the basis of 105 overhaul. The effects before and after implementation are compared as follows:
table 1: liquid level and pressure fluctuation amplitude comparison before and after implementation of change
As shown in particular in figures 1 and 2.
Claims (8)
1. A method for reducing disturbance of a secondary loop of a power plant during grid connection is characterized by comprising the following steps:
step 1: using the on-off state of a generator outlet breaker and the pressure of a turbine impulse stage as judgment conditions for judging whether the turbine is connected with the power grid or not;
step 2: closing a bypass valve after judging that the turbine is successfully connected to the grid;
and step 3: reset valves and logic.
2. The method for reducing the disturbance of the secondary loop of the power plant during the grid connection of claim 1, wherein the method comprises the following steps: the circuit breaker has an opening state and a closing state, impulse stage pressure is low before grid connection and high after grid connection, and the circuit breaker state and impulse stage pressure signals are combined and used for judging the state of the steam turbine.
3. The method for reducing the disturbance of the secondary loop of the power plant during grid connection as claimed in claim 2, wherein: the state of the steam turbine is judged to be,
the impulse stage is low in pressure, and the breaker is disconnected and is in a shutdown state.
4. The method for reducing the disturbance of the secondary loop of the power plant during the grid connection of claim 2, wherein the method comprises the following steps: the state of the steam turbine is judged to be,
the impulse stage pressure is high, and the breaker is disconnected and is in an impulse state.
5. The method for reducing the disturbance of the secondary loop of the power plant during the grid connection of claim 2, wherein the method comprises the following steps: the state of the steam turbine is judged to be,
the impulse stage pressure is high, the breaker is closed, and the grid-connected state is realized.
6. The method for reducing the disturbance of the secondary loop of the power plant during the grid connection of claim 2, wherein the method comprises the following steps: the state of the steam turbine is judged to be,
after grid connection, the impulse stage pressure is kept high, the breaker is kept closed, and the grid connection is successful.
7. The method for reducing the disturbance of the secondary loop of the power plant during grid connection as claimed in claim 1, wherein: and 2, after the breaker is changed from the off state to the on state, checking that the pressure of the impulse stage is higher than a fixed value, considering that the grid connection is successful, closing a bypass valve, and executing 3 if the pressure or the state of the breaker changes and does not meet the condition of successful grid connection after the grid connection is successful.
8. The method for reducing the disturbance of the secondary loop of the power plant during the grid connection of claim 1, wherein the method comprises the following steps: and 3, when the grid connection is successful and the power is increased, the opening degrees of the two reset and opened bypass valves are calculated according to normal control logic.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110363505.4A CN115182794A (en) | 2021-04-02 | 2021-04-02 | Method for reducing disturbance of two loops of power plant during grid connection |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110363505.4A CN115182794A (en) | 2021-04-02 | 2021-04-02 | Method for reducing disturbance of two loops of power plant during grid connection |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN115182794A true CN115182794A (en) | 2022-10-14 |
Family
ID=83511226
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202110363505.4A Pending CN115182794A (en) | 2021-04-02 | 2021-04-02 | Method for reducing disturbance of two loops of power plant during grid connection |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN115182794A (en) |
Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20060034974A (en) * | 2004-10-20 | 2006-04-26 | 한국전력공사 | A method for anticipating and controlling overspeed of a steam turbine according to load alteration of generator |
| KR101314123B1 (en) * | 2013-07-23 | 2013-10-04 | 조영숙 | Switchgear for controling peak using distributed generation of grid connected |
| CN103811090A (en) * | 2012-11-14 | 2014-05-21 | 中国广东核电集团有限公司 | Pressurized water reactor nuclear power station steam generator water level control method and system |
| CN105372991A (en) * | 2015-11-25 | 2016-03-02 | 国家电网公司 | Heat supply unit multi-coal mixed combustion condition main steam pressure fluctuation-overcoming control method |
| CN107165686A (en) * | 2016-03-08 | 2017-09-15 | 北京国电智深控制技术有限公司 | A kind of double reheat fired power generating unit bypass control method and system |
| CN108104881A (en) * | 2017-12-01 | 2018-06-01 | 中国神华能源股份有限公司 | High pressure turbine by control method, system and machine readable storage medium |
| CN109339872A (en) * | 2018-10-18 | 2019-02-15 | 中广核工程有限公司 | Nuclear power station steam turbine control system |
| CN110821579A (en) * | 2019-10-09 | 2020-02-21 | 中国能源建设集团华中电力试验研究院有限公司 | Steam turbine-generator safety protection system and method applied to large power plant |
| CN112564164A (en) * | 2020-11-25 | 2021-03-26 | 河北蔚州能源综合开发有限公司 | Generator grid-connected signal synthesis mode |
-
2021
- 2021-04-02 CN CN202110363505.4A patent/CN115182794A/en active Pending
Patent Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20060034974A (en) * | 2004-10-20 | 2006-04-26 | 한국전력공사 | A method for anticipating and controlling overspeed of a steam turbine according to load alteration of generator |
| CN103811090A (en) * | 2012-11-14 | 2014-05-21 | 中国广东核电集团有限公司 | Pressurized water reactor nuclear power station steam generator water level control method and system |
| KR101314123B1 (en) * | 2013-07-23 | 2013-10-04 | 조영숙 | Switchgear for controling peak using distributed generation of grid connected |
| CN105372991A (en) * | 2015-11-25 | 2016-03-02 | 国家电网公司 | Heat supply unit multi-coal mixed combustion condition main steam pressure fluctuation-overcoming control method |
| CN107165686A (en) * | 2016-03-08 | 2017-09-15 | 北京国电智深控制技术有限公司 | A kind of double reheat fired power generating unit bypass control method and system |
| CN108104881A (en) * | 2017-12-01 | 2018-06-01 | 中国神华能源股份有限公司 | High pressure turbine by control method, system and machine readable storage medium |
| CN109339872A (en) * | 2018-10-18 | 2019-02-15 | 中广核工程有限公司 | Nuclear power station steam turbine control system |
| CN110821579A (en) * | 2019-10-09 | 2020-02-21 | 中国能源建设集团华中电力试验研究院有限公司 | Steam turbine-generator safety protection system and method applied to large power plant |
| CN112564164A (en) * | 2020-11-25 | 2021-03-26 | 河北蔚州能源综合开发有限公司 | Generator grid-connected signal synthesis mode |
Non-Patent Citations (1)
| Title |
|---|
| 霍雷;任延宝;孙小龙;赵书宇;: "某核电汽轮发电机组并网后最小负荷过大原因分析和优化措施", 黑龙江电力, no. 05, 15 October 2013 (2013-10-15) * |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN104633638B (en) | The integrated control method of the shutdown not blowing out function of power plant FCB | |
| CN202230373U (en) | Automatic power plant start up & shut down system of gas-steam combined cycle unit | |
| CN102393688A (en) | One-key start-stop control system for fuel gas and steam combined cycle unit | |
| CN101598328A (en) | The Steam Temperature for Boiler control method and the isolated plant of big rate of load change | |
| CN102620277A (en) | Method and system for controlling load-shedding working condition of supercritical unit | |
| CN115182794A (en) | Method for reducing disturbance of two loops of power plant during grid connection | |
| CN112197610B (en) | Primary frequency modulation composite control system of coal-fired unit and working method thereof | |
| CN113405088A (en) | Three-impulse frequency conversion automatic adjusting method | |
| CN111896241A (en) | Method and device for testing partial stroke activity of steam turbine valve | |
| CN112944322B (en) | Control method for water supply system in FCB process of thermal generator set | |
| CN109028004A (en) | Peak regulation gas fired-boiler feedwater flow and pressure double-balance control system | |
| JP2578328B2 (en) | Output control method for back pressure turbine generator | |
| CN111856940A (en) | Control method and device for low-load operation of thermal power generating unit and storage medium | |
| CN111525608A (en) | Method and device for realizing power regulation of thermal power generating unit based on rapid load shedding | |
| CN112117783A (en) | Thermal power generating unit power grid low-frequency accident frequency modulation method | |
| CN109488394A (en) | The control method that million nuclear steam turbine control system machine heaps are coordinated | |
| CN113027545B (en) | Bypass control method for stabilizing steam drum liquid level of gas-steam combined cycle unit | |
| CN113091047B (en) | Control method for main steam desuperheating water of unit | |
| JPS59203812A (en) | Water supply system to deaerator | |
| CN114688520B (en) | Auxiliary control method and system for liquid level of steam generator of nuclear power station | |
| JP2004245069A (en) | Speed controller of combined cycle power generation plant | |
| CN212563519U (en) | Primary overspeed protection system of hydropower station | |
| Carvalho et al. | The influence of control system design on the dynamic response characteristics of thermal power plants | |
| Wan et al. | Tuning of digital control system for 350 MW coal-fired unit for improved controllability and pick-up performance | |
| Li et al. | Research on the Control under the Participation of Heat Storage Device and Fast Cut Back Control Strategies in Isolated Grid |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |