阅读说明：本技术 一种抽水蓄能机组全状态定子电压调节方法 (Method for adjusting voltage of all-state stator of pumped storage unit ) 是由 吴昊 彭涛 卢勇 方峻 代雄 杨铭轩 贺儒飞 陈凤华 黄中杰 邱小波 茹浩 梁 于 2019-12-10 设计创作，主要内容包括：本发明公开了一种抽水蓄能机组全状态定子电压调节方法,属于电力调度控制的技术领域。本发明的调节方法基于由“上/下位机、励磁系统、变送器、主变低压侧电压互感器和发变组”构成的抽水蓄能机组电压控制环结构,具体过程包括了判断机组稳态工况、励磁系统控制发电机定子电压与上位机的电压设定值保持一致、判断机组是否处于暂态工况、维持励磁系统在暂态工况下发电机的定子电压稳定、或者主变低压侧的电压值作为发电机的定子电压反馈给励磁系统维持定子电压稳定的步骤。利用本发明方法,可以作为现有发电机无功控制功能的备用控制手段,避免现有机组中主用无功控制环一旦故障后机组需要停机问题,稳定电力生产。(The invention discloses a method for adjusting the voltage of a full-state stator of a pumped storage unit, and belongs to the technical field of power dispatching control. The method is based on a voltage control ring structure of the pumped storage unit, which is composed of an upper computer/a lower computer, an excitation system, a transmitter, a main transformer low-voltage side voltage transformer and a generator-transformer set, and comprises the steps of judging the steady-state working condition of the unit, controlling the voltage of a generator stator to be consistent with the voltage set value of the upper computer by the excitation system, judging whether the unit is in the transient working condition, maintaining the voltage of the generator stator to be stable under the transient working condition by the excitation system, or feeding the voltage value of the low-voltage side of the main transformer as the voltage of the generator stator back to the excitation system to maintain the voltage of. The method can be used as a standby control means of the reactive control function of the existing generator, avoids the problem that the main reactive control loop in the existing unit needs to be shut down once the main reactive control loop fails, and stabilizes the power production.)

1. A pumped storage unit all-state stator voltage adjusting method is carried out based on a pumped storage unit voltage control ring, wherein the pumped storage unit voltage control ring is composed of an upper computer, a lower computer, an excitation system with an information feedback card, a generator-transformer group, a transmitter and a main transformer low-voltage side voltage transformer, and the excitation system is also provided with a main excitation channel and a standby excitation channel; characterized in that the method comprises the following steps:

s1, monitoring whether the unit is in a steady state working condition or not when the pumped storage unit lower computer is connected to the grid and reporting to an upper computer; if not, go to step S3; if so, the upper computer sets a stator voltage set value according to the data reported by the lower computer;

s2, the lower computer receives a stator voltage set value sent by the upper computer, the excitation system feeds back a stator voltage set value of an internal generator-transformer set thereof, then the difference value of the stator voltage set value and the stator voltage set value is calculated, the lower computer sends an excitation adding/reducing instruction to the excitation system according to the difference value, so that the stator voltage set value of the excitation system is consistent with the stator voltage set value, and then the generator-transformer set stator voltage controlled by the excitation system is the same as the stator voltage set value of the upper computer;

s3, the lower computer monitors whether the unit is in a working condition of converting power generation to shutdown or phase modulation of water pumping to water pumping when the unit is connected to the grid, and transmits monitoring data to the upper computer; if not, go to step S7; if yes, go to step S4;

s4, the lower computer receives a generator-transformer set stator voltage set value fed back by the excitation system and a main transformer low-voltage side voltage value of a main transformer low-voltage side voltage transformer fed back by the transmitter, calculates a difference value of the generator-transformer set stator voltage set value and the main transformer low-voltage side voltage value, and then sends an excitation adding/subtracting instruction to the excitation system according to the difference value, so that generator-transformer set stator voltage controlled by the excitation system is consistent with main transformer low-voltage side voltage;

s5, on the basis of the step S4, if the lower computer detects that the voltage set value of the generator-transformer unit stator fed back by the excitation system cannot be consistent with the voltage value of the low-voltage side of the main transformer, the lower computer judges that the stator voltage control function of the main excitation channel of the excitation system is in a fault state, and then the step S6 is executed;

s6, the lower computer receives a stator voltage set value of the generator-transformer set controlled by the excitation system, the stator voltage set value is used as a stator voltage set value of the upper computer and is returned to the excitation system, and the excitation system starts a standby excitation channel to control the stator voltage of the generator-transformer set according to the stator voltage set value so as to maintain the stator voltage of the generator-transformer set unchanged;

s7, the lower computer monitors whether the unit is in any working condition of conversion halt to no-load, conversion halt to water pumping phase modulation, water pumping to conversion halt, and conversion halt to dragging when the unit is connected to the grid, and transmits monitoring data to the upper computer; if not, the unit is in a steady state working condition, and the unit returns to S2; if yes, go to step S8;

and S8, the lower computer receives the voltage at the low voltage side of the main transformer fed back by the transmitter and the set value of the voltage of the generator-transformer set fed back by the excitation system, the set value of the voltage of the stator of the generator-transformer set at present is taken as a new set value of the voltage of the stator of the upper computer and is directly issued to the excitation system, and the excitation system controls the voltage of the stator of the generator-transformer set according to the set value of the voltage of the stator to maintain stability.

2. The pumped-storage group all-state stator voltage regulation method according to claim 1, characterized in that: the steady state working condition in the step S1 means that the unit is in any one of the working states of power generation, water pumping phase modulation and power generation phase modulation.

3. The pumped-storage group full-state stator voltage regulation method according to claim 1, wherein the more specific process in step S2 is:

s21, the lower computer receives a stator voltage set value set by the upper computer in the step S1, and meanwhile, the lower computer receives a current stator voltage set value of a generator-transformer set fed back by an excitation system;

s22, the lower computer calculates the difference value between the stator voltage set value of the upper computer and the current stator voltage set value of the generator-transformer set;

and S23, the lower computer issues excitation addition/subtraction to the excitation system according to the difference value, drives the excitation system to control the voltage of the generator-transformer set stator through a main excitation channel until the difference value between the generator-transformer set stator voltage fed back by the excitation system and a set value of the stator voltage is zero, and indicates that the generator-transformer set stator voltage is consistent with the set value of the upper computer stator voltage.

4. The pumped-storage group full-state stator voltage regulation method according to claim 1, wherein the more specific process in step S4 is:

s41, the lower computer receives a generator-transformer set stator voltage set value fed back by the excitation system and a main transformer low-voltage side voltage value fed back by the transmitter;

s42, the lower computer calculates the difference value of the two voltage values in the S41 and sends an excitation adding/subtracting instruction to the excitation system according to the difference value;

s43, under the action of an excitation adding/subtracting instruction, the main excitation channel of the excitation system continuously adjusts the voltage of the generator-transformer set stator until the voltage of the generator-transformer set stator is consistent with the voltage value of the low-voltage side of the main transformer.

5. The pumped-storage group all-state stator voltage regulation method according to claim 1, characterized in that: in step S5, when the excitation system is under the action of the excitation adding/subtracting command and the stator voltage setting value fed back by the excitation system received by the lower computer is not changed in step S4, it is determined that the voltage control of the excitation system main excitation channel fails, which indicates that the stator voltage of the excitation generator set is not correctly controlled by the main excitation channel of the excitation system.

6. The pumped-storage group all-state stator voltage regulation method according to claim 1, characterized in that: in step S6, the lower computer sets the stator voltage controlled by the excitation system as the upper computer stator voltage set value before the excitation system main excitation channel failure is detected.

7. The pumped-storage group full-state stator voltage regulation method according to claims 1-6, characterized in that in step S8, the more specific process is:

s81, monitoring whether the primary excitation channel fails or not by the lower computer; if the fault occurs, starting a standby excitation channel, and then executing the step S82; if no, directly executing step S82;

and S82, the lower computer receives a generator-transformer set stator voltage set value fed back by the excitation system, the generator-transformer set voltage set value is used as an upper computer stator voltage set value and is returned to the excitation system, and the excitation system controls the stator voltage of the generator-transformer set according to the set value so as to keep the unit stable in operation.

Technical Field

The invention relates to the technical field of power dispatching control, in particular to a voltage control method for an energy storage unit.

Background

The pumped storage unit plays important roles of frequency modulation and phase modulation, peak clipping and valley filling, accident standby, power system voltage and cycle stabilization and other generator unit operation efficiency guarantee in a power grid. The lower computer of the monitoring system is one of core systems for controlling the operation of the pumped storage unit, realizes the flow control, signal monitoring, alarm trip of each working condition of the storage unit, communicates with the upper computer and other systems, and controls the frequency, power and voltage of the unit according to the instruction of an attendant or a dispatcher or established logic. One of the core functions realized by the lower computer is to operate a full-state stator voltage regulation strategy of the pumped storage unit, receive an upper-level command, and issue a voltage command to an excitation system, so that the stator voltage is in a required interval.

The voltage of the existing pumped storage unit is realized by a reactive control loop strategy, corresponding electric hardware of the reactive control loop is usually integrated in an excitation system of the generating set, and a weak current electronic circuit is arranged to intelligently monitor equipment. The reactive power control strategy is to use the reactive power as a controlled object and realize the reactive output of the unit and the stability of the voltage through the physical relation between the reactive power and the voltage. However, when the reactive control loop has defects (for example, the reactive measurement fails), the whole unit cannot avoid serious consequences of fault shutdown and reactive overshoot, which causes serious production safety accidents and economic losses.

Disclosure of Invention

In order to solve one or more problems in the background art, the invention provides a method for adjusting the voltage of a full-state stator of a pumped storage unit, which has the following specific technical scheme:

a pumped storage unit all-state stator voltage regulation method is carried out based on a pumped storage unit voltage control ring, the pumped storage unit voltage control ring operating the method is composed of an upper computer, a lower computer, an excitation system with an information feedback card, a generator-transformer group, a transmitter and a main transformer low-voltage side voltage transformer, wherein the excitation system is also provided with a main/standby excitation channel; the method comprises the following steps:

s1, monitoring whether the unit is in a steady state working condition or not when the pumped storage unit lower computer is connected to the grid and reporting to an upper computer; if not, go to step S3; if so, the upper computer sets a stator voltage set value according to the state data reported by the lower computer;

s2, the lower computer receives a stator voltage set value sent by the upper computer, the excitation system feeds back a stator voltage set value of an internal generator-transformer set thereof, then the difference value of the stator voltage set value and the stator voltage set value is calculated, the lower computer sends an excitation adding/reducing instruction to the excitation system according to the difference value, so that the stator voltage set value of the excitation system is consistent with the stator voltage set value, and then the generator-transformer set stator voltage controlled by the excitation system is the same as the stator voltage set value of the upper computer;

s3, the lower computer monitors whether the unit is in a working condition of converting power generation to shutdown or phase modulation of water pumping to water pumping when the unit is connected to the grid, and transmits monitoring data to the upper computer; if not, go to step S7; if yes, go to step S4;

s4, the lower computer receives a generator-transformer set stator voltage set value fed back by the excitation system and a main transformer low-voltage side voltage value of a main transformer low-voltage side voltage transformer fed back by the transmitter, calculates a difference value of the generator-transformer set stator voltage set value and the main transformer low-voltage side voltage value, and then sends an excitation adding/subtracting instruction to the excitation system according to the difference value, so that generator-transformer set stator voltage controlled by the excitation system is consistent with main transformer low-voltage side voltage;

s5, on the basis of the step S4, if the lower computer detects that the voltage set value of the generator-transformer unit stator fed back by the excitation system cannot be consistent with the voltage value of the low-voltage side of the main transformer, the lower computer judges that the stator voltage control function of the main excitation channel of the excitation system is in a fault state, and then the step S6 is executed;

s6, the lower computer receives a stator voltage set value of the generator-transformer set controlled by the excitation system, the stator voltage set value is used as a stator voltage set value of the upper computer and is returned to the excitation system, and the excitation system starts a standby excitation channel to control the stator voltage of the generator-transformer set according to the stator voltage set value so as to maintain the stator voltage of the generator-transformer set unchanged;

s7, the lower computer monitors whether the unit is in any working condition of conversion halt to no-load, conversion halt to water pumping phase modulation, water pumping to conversion halt, and conversion halt to dragging when the unit is connected to the grid, and transmits monitoring data to the upper computer; if not, the unit is in a steady state working condition, and the unit returns to S2; if yes, go to step S8;

and S8, the lower computer receives the voltage at the low voltage side of the main transformer fed back by the transmitter and the set value of the voltage of the generator-transformer set fed back by the excitation system, the set value of the voltage of the stator of the generator-transformer set at present is taken as a new set value of the voltage of the stator of the upper computer and is directly issued to the excitation system, and the excitation system controls the voltage of the stator of the generator-transformer set according to the set value of the voltage of the stator to maintain stability.

Further, the steady state condition in step S1 means that the unit is in any one of the operating states of power generation, water pumping phase modulation, and power generation phase modulation.

Further, the more specific procedure in step S2 is:

s21, the lower computer receives a stator voltage set value set by the upper computer in the step S1, and meanwhile, the lower computer receives a current stator voltage set value of a generator-transformer set fed back by an excitation system;

s22, the lower computer calculates the difference value between the stator voltage set value of the upper computer and the current stator voltage set value of the generator-transformer set;

and S23, the lower computer issues excitation addition/subtraction to the excitation system according to the difference value, drives the excitation system to control the voltage of the generator-transformer set stator through a main excitation channel until the difference value between the generator-transformer set stator voltage fed back by the excitation system and a set value of the stator voltage is zero, and indicates that the generator-transformer set stator voltage is consistent with the set value of the upper computer stator voltage.

Further, the more specific procedure in step S4 is:

s41, the lower computer receives a generator-transformer set stator voltage set value fed back by the excitation system and a main transformer low-voltage side voltage value fed back by the transmitter;

s42, the lower computer calculates the difference value of the two voltage values in the S41 and sends an excitation adding/subtracting instruction to the excitation system according to the difference value;

s43, under the action of an excitation adding/subtracting instruction, the main excitation channel of the excitation system continuously adjusts the voltage of the generator-transformer set stator until the voltage of the generator-transformer set stator is consistent with the voltage value of the low-voltage side of the main transformer.

Further, in step S5, on the basis of step S4, when the excitation system is under the action of the excitation adding/subtracting command, and the stator voltage setting value fed back by the excitation system received by the lower computer is not changed, it indicates that the main excitation channel of the excitation system does not correctly control the stator voltage of the excitation group, and at this time, it is determined that the voltage control of the main excitation channel of the excitation system has a fault.

Further, in step S6, the lower computer takes the stator voltage controlled by the field system before the field system main field channel failure is detected as the upper computer stator voltage setting value.

Further, the more specific procedure in step S8 is:

s81, monitoring whether the primary excitation channel fails or not by the lower computer; if the fault occurs, starting a standby excitation channel, and then executing the step S82; if no, directly executing step S82;

and S82, the lower computer receives a generator-transformer set stator voltage set value fed back by the excitation system, the generator-transformer set voltage set value is used as an upper computer stator voltage set value and is returned to the excitation system, and the excitation system controls the stator voltage of the generator-transformer set according to the set value so as to keep the unit stable in operation.

Compared with the existing working condition adjusting method of the energy storage unit only using one reactive control ring, the all-state stator voltage adjusting method of the pumped storage unit has the advantages that:

the method provided by the invention is used as a standby control means, and makes up the defect that most pumped storage power plants only have a reactive power control strategy but not a voltage control strategy. The voltage control strategy is used as a quick and simple control mode and can be used as a standby control loop after a reactive control loop fails, when the original main reactive control of the energy storage unit fails, the voltage of a stator of the generator can be stabilized in time according to specific working conditions, the operation of the generator is stabilized, the serious consequences of fault shutdown and reactive power overshoot are avoided, and the production safety of the power system is ensured.

Drawings

FIG. 1 is a flow chart of one of the methods of the present invention;

fig. 2 is a schematic block diagram of the system operating according to the method of fig. 1.

Detailed Description

The drawings are for illustrative purposes only and are not to be construed as limiting the patent. Certain features or steps of the drawings may be omitted, enlarged or reduced to better illustrate the embodiments, and are not intended to represent the size or composition of the actual product or method. It will be understood by those skilled in the art that certain well-known structures or steps in the drawings and descriptions thereof may be omitted.

The technical scheme of the invention is further explained in a mode of combining the preparation method and the components by combining the attached drawings and the examples.

Referring to fig. 1 and 2, a voltage control loop of the pumped storage unit is composed of an upper computer, a lower computer, a transmitter, a main transformer low-voltage side voltage transformer (PT), a generator-transformer set and an excitation system. The excitation system contains an information feedback card for feeding back the running condition of the equipment to the lower computer, and the information feedback card feeds back the data of the lower computer in real time. The excitation system is also provided with a main excitation channel and a standby excitation channel for carrying out excitation operation on the discharge machine stator of the generator-transformer set so as to ensure that a standby excitation path can independently realize the function when the excitation system has a structural fault of adding/reducing voltage to/from the original generator stator of the generator-transformer set. In a voltage control loop of the pumped storage unit, in order to judge the working condition of the unit, relevant data of switch states, disconnecting link states, valve states, protection systems, auxiliary machine states and electrical quantities (including power, voltage, frequency, current and the like) in a generator-transformer unit, a transmitter and an excitation system are all fed back to a lower computer and then reported to an upper computer for judgment.

The method for adjusting the voltage of the all-state stator of the pumped storage unit comprises the following specific steps:

the first step, the lower computer of the pumped storage unit respectively receives state data of main switches, disconnecting links, valves, protection systems, auxiliary machines and the electrical quantities (including power, voltage, frequency, current and the like) of the unit and reports the state data to the upper computer; the lower computer judges whether the unit is in any one of four steady-state working conditions of power generation, water pumping phase modulation and power generation phase modulation or not when the unit is connected to the grid according to the monitored state data; if yes, executing the second step; if not, executing the third step.

Secondly, regulating and controlling the voltage of the generator-transformer group stator;

the method comprises the following steps that firstly, an upper computer sets a stator voltage set value according to a program instruction and state data monitored by a lower computer and sends the stator voltage set value to the lower computer, and the lower computer receives generator-transformer group stator voltage which is fed back by an excitation system and is currently controlled by the excitation system, namely the generator-transformer group stator voltage set value of the excitation system;

in the second small step, the lower computer calculates the difference value of the two voltage values, sends an excitation adding/subtracting instruction according to the difference value, and starts a main excitation channel to carry out the control operation of the next small step on the voltage of the generator-transformer group stator;

and thirdly, feeding back the current stator voltage of the generator-transformer set by the excitation system, calculating the difference value between the current stator voltage and the set value of the upper computer stator voltage by the lower computer, and stopping issuing an excitation adding/reducing instruction until the difference value is zero so that the stator voltage of the generator-transformer set is consistent with the set value of the upper computer stator voltage.

Thirdly, the lower computer respectively receives a voltage value at the low-voltage side of the main transformer fed back by the transmitter and a set voltage value of a stator of the generator-transformer set fed back by the excitation system, judges whether the unit is in one of working conditions from power generation to conversion shutdown and from water pumping phase modulation to water pumping, and reports the conditions to the upper computer; if yes, executing the fourth step; if not, executing the seventh step.

Fourthly, regulating and controlling the voltage of the generator-transformer group stator;

the first small step, the lower computer calculates the difference value of the voltage value at the low-voltage side of the main transformer and the voltage set value of the stator of the generator-transformer unit according to the feedback voltage value at the low-voltage side of the main transformer and the voltage set value of the stator of the generator-transformer unit;

secondly, the lower computer issues an excitation increasing/reducing instruction to the excitation system according to the difference value;

thirdly, controlling the voltage of the generator-transformer group stator by the excitation system through the main excitation channel under the regulation of the instruction; and the excitation system feeds back the currently controlled stator voltage value to the lower computer in real time until the difference value between the currently controlled stator voltage value and the main transformer low-voltage side voltage value is zero, so that the generator-transformer set stator voltage is consistent with the main transformer low-voltage side voltage.

Fifthly, on the basis of the third small step of the fourth step, if the voltage of the current generator-transformer group controlled by the feedback of the excitation system is not changed after the excitation adding/subtracting instruction is issued by the lower computer, which indicates that the main excitation channel of the excitation system is in fault, the sixth step is executed; and if the third step of the fourth step can be executed correctly, the unit finishes the adjusting process, keeps the current state until a new working condition appears, and then enters the next round of adjustment.

And sixthly, the lower computer receives a stator voltage set value controlled by the excitation system before the main excitation channel fails, returns the voltage set value to the excitation system as an upper computer stator voltage set value, issues an instruction for starting the standby excitation channel, and controls the stator voltage of the generator-transformer set to be consistent with the stator voltage set value through the standby excitation channel.

Seventhly, the lower computer monitors whether the unit is in any one of four working conditions of switching halt to no-load, switching halt to pumping phase modulation, pumping to switching halt and switching halt to dragging, and reports data to the upper computer; if not, the unit is in the steady state working condition, and the unit returns to the second step; if yes, executing the eighth step.

Step eight, adjusting the stator voltage;

the first step, the lower computer monitors whether the excitation system feeds back the main excitation channel to be in fault; if yes, starting a standby excitation channel, and then executing a second small step; if not, only directly executing the second small step;

and secondly, receiving the voltage set value of the generator-transformer set before the transient working condition fed back by the excitation system by the lower computer, and directly returning the voltage set value of the generator-transformer set to the excitation system as the voltage set value of the upper computer stator so as to enable the voltage of the generator-transformer set to be controlled by the excitation system to be kept unchanged.

By utilizing the method for adjusting the voltage of the all-state stator of the pumped storage unit, the defect that most pumped storage power plants only have a reactive power control strategy but not a voltage control strategy is overcome. The voltage control strategy is used as a quick and simple control mode and can be used as a standby control loop after the reactive control loop fails. When the original main reactive control loop of the energy storage unit fails or even after the main transformer voltage has a feedback fault, the method can start the voltage control loop in time to set the voltage value of the lower computer to follow the excitation system, thereby stabilizing the voltage of the stator of the generator, stabilizing the operation of the generator, avoiding the serious consequences of fault shutdown and reactive power overshoot and ensuring the production safety of the power system.

Finally, the above embodiments are only for illustrating the technical solutions of the present invention and not for limiting, although the present invention has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions may be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all of them should be covered in the claims of the present invention.