阅读说明：本技术 用于对电网频率瞬态事件进行快速负荷支持的方法和系统 (Method and system for fast load support for grid frequency transient events ) 是由 路易斯·费尔南多·古铁雷斯 约翰·T·阮 阿德南·法里德·萨法尔 尤利玛·罗阿 乔斯·卡洛斯 于 2020-09-03 设计创作，主要内容包括：本发明题为“用于对电网频率瞬态事件进行快速负荷支持的方法和系统”。本申请提供了用于对电网频率瞬态事件进行快速负荷支持的方法和系统。示例性系统可包括：具有第一控制器的涡轮；联接到涡轮的发电机,其中发电机被构造成向电网提供电力；和被构造成向发电机的转子提供直流(DC)电压和DC电流的励磁机。励磁机可包括第二控制器,该第二控制器被构造成监测与电网相关联的第一组电特性,基于第一组电特性来确定电网上存在瞬态事件,以及将瞬态事件的通知发送到第一控制器。(The invention provides a method and system for fast load support for grid frequency transient events. Methods and systems for fast load support for grid frequency transient events are provided. An exemplary system may include: a turbine having a first controller; a generator coupled to the turbine, wherein the generator is configured to provide electrical power to a power grid; and an exciter configured to provide a Direct Current (DC) voltage and a DC current to a rotor of the generator. The exciter machine may include a second controller configured to monitor a first set of electrical characteristics associated with the electrical grid, determine that a transient event exists on the electrical grid based on the first set of electrical characteristics, and send a notification of the transient event to the first controller.)

1. A system for providing rapid load support using a gas turbine, the system comprising:

a turbine including a first controller;

a generator coupled to the turbine, wherein the generator is configured to provide power to a power grid; and

an exciter machine configured to provide a Direct Current (DC) voltage and a DC current to a rotor of the generator, wherein the exciter machine comprises a second controller configured to:

monitoring a first set of electrical characteristics associated with the electrical grid;

determining that a transient event exists on the electrical grid based on the first set of electrical characteristics; and

sending a notification of the transient event to the first controller;

wherein the first controller is configured to adjust operation of the turbine based on the notification.

2. The system of claim 1, wherein the first controller is configured to adjust operation of the turbine based on modeled values of electrical power.

3. The system of claim 1, wherein the first controller is configured to generate a modeled value of electrical power.

4. The system of claim 3, wherein the modeled value is a megawatt modeled value generated based on a compressor discharge pressure of a compressor at the turbine.

5. The system of claim 3, wherein the modeled values temporally replace actual kinetic energy readings at a wattmeter of the turbine.

6. The system of claim 1, wherein the first controller is configured to adjust a dynamics of a fuel demand on a fuel valve regulator of the turbine.

7. The system of claim 6, wherein the dynamics of fuel demand are flexible dynamics.

8. The system of claim 6, wherein the dynamics of fuel demand are adjusted by temporarily replacing a first dynamics with a second dynamics.

9. The system of claim 8, wherein the second dynamics results in a controlled acceleration of the turbine.

10. The system of claim 1, wherein the second controller determines that the transient event is present on the electrical grid when a frequency, voltage, current, power, or power factor associated with the electrical grid increases or decreases by more than a threshold.

11. The system of claim 1, wherein the second controller is further configured to:

sensing a rate of change of electrical frequency at a terminal of the generator; and

determining a rate of change of axis acceleration;

wherein the rate of change is one of the electrical characteristics in the first set of electrical characteristics.

12. The system of claim 1, wherein the first controller is configured to adjust a master frequency algorithm.

13. The system of claim 1, wherein the first controller is configured to determine a grid frequency boundary and increase a valve response time to avoid oscillations.

14. The system of claim 1, wherein the turbine is an aeroderivative gas turbine.

15. A method for providing improved load support for grid frequency transient events, the method comprising:

monitoring, by a first controller, a first set of electrical characteristics associated with an electrical grid;

determining, by the first controller, that a transient event exists on the electrical grid based on the first set of electrical characteristics; and

sending a notification of the transient event to a second controller;

wherein the second controller is configured to adjust operation of the turbine based on the notification by: (i) adjusting dynamics of fuel demand to a fuel valve regulator of the turbine, and (ii) adjusting a primary frequency algorithm.

Technical Field

The present application and the resultant patent relate generally to gas turbine systems and, more particularly, to providing fast load support in response to grid frequency transient events.

Background

A power plant or power generation system may utilize other primary energy sources to generate electricity. For example, a prime mover such as a gas turbine is a rotating mechanical device having a gas turbine shaft that drives a generator to supply electrical power to a power grid. The grid in turn supplies power to various power consumers. To ensure that the power generation system operates efficiently, the turbine shaft speed and the resulting grid frequency should be synchronized with each other over an operating range. When the grid frequency changes suddenly due to a transient event, a power outage may result.

For smaller grids, such as those providing load capacities of about 500 Megawatts (MW), the negative effects of transient events such as sudden changes in the grid frequency are magnified. Smaller grids are generally less stable than larger grids, as load changes of the same magnitude will result in larger frequency changes. Thus, smaller grids tend to experience frequency changes more frequently than larger grids. Lack of stability can lead to grid outages and/or power losses. Therefore, there is a need for systems and methods that provide fast load support for grid frequency transient events to enhance the power stability of the grid.

Disclosure of Invention

The present application and the resultant patent provide a system for providing rapid load support using a gas turbine. The system may include: a turbine having a first controller; a generator coupled to the turbine, wherein the generator is configured to provide electrical power to a power grid; and an exciter configured to provide a Direct Current (DC) voltage and a DC current to a rotor of the generator. The exciter machine may include a second controller configured to monitor a first set of electrical characteristics associated with the electrical grid, determine that a transient event exists on the electrical grid based on the first set of electrical characteristics, and send a notification of the transient event to the first controller. The first controller may be configured to adjust operation of the turbine based on the notification.

The present application and the resultant patent also provide methods for providing improved load support for grid frequency transient events. The method can comprise the following steps: the method includes monitoring, by a first controller, a first set of electrical characteristics associated with an electrical grid, determining, by the first controller, a presence of a transient event on the electrical grid based on the first set of electrical characteristics, and sending a notification of the transient event to a second controller. The second controller may be configured to adjust operation of the turbine based on the notification by: (i) adjusting dynamics of fuel demand to a fuel valve regulator of the turbine, and (ii) adjusting a primary frequency algorithm.

The present application and the resultant patent also provide a system for providing fast load support. The system may include: a prime mover having a first controller, such as an aeroderivative gas turbine; a generator coupled to the aeroderivative gas turbine, wherein the generator is configured to provide electrical power to an electrical grid; and an exciter configured to provide a Direct Current (DC) voltage and a DC current to a rotor of the generator. The exciter machine may include a second controller configured to monitor a first set of electrical characteristics associated with the electrical grid, determine that a transient event exists on the electrical grid based on the first set of electrical characteristics, and send a notification of the transient event to the first controller. The first controller may be configured to adjust operation of the aeroderivative gas turbine based on the notification by: (i) adjusting dynamics of fuel demand on a fuel valve regulator of an aeroderivative gas turbine, and (ii) adjusting a primary frequency algorithm.

These and other features and improvements of the present application and the resultant patent will become apparent to one of ordinary skill in the art upon review of the following detailed description when taken in conjunction with the several drawings and the appended claims.

Drawings

FIG. 1 is a schematic diagram of a power generation system.

Fig. 2 is a schematic diagram of a control system for an exciter and gas turbine as may be described herein.

Fig. 3 is an exemplary process flow for fast load support for grid frequency transient events as may be described herein.

Fig. 4 is an exemplary process flow for fast load support for grid frequency transient events as may be described herein.

Detailed Description

Referring now to the drawings, in which like numerals refer to like elements throughout the several views. FIG. 1 is a schematic diagram of a power generation system 100. The power generation system 100 may include a prime mover that generates power from other primary energy sources. An exemplary prime mover may be a gas turbine 150, such as an aeroderivative gas turbine, and may be a rotating mechanical device having a gas turbine shaft that drives a generator to supply electrical power to a power grid that supplies electrical power to users. Other embodiments may include different types of turbines, such as steam turbines. To achieve fault-free operation, the turbine shaft speed and the resulting grid frequency must be maintained within an operating range.

The gas turbine 150 may be coupled to a generator 130 that powers a power grid 140. The gas turbine engine 150 may include a compressor. The compressor compresses an incoming flow of air. The compressor delivers a compressed flow of air to the combustor. The combustor mixes the compressed flow of air with a pressurized flow of fuel and ignites the mixture, thereby creating a flow of combustion gases. The combustion gas stream is then delivered to a turbine. The flow of combustion gases drives the turbine in order to produce mechanical work. The mechanical work produced in the turbine drives the compressor via the shaft and drives an external load such as generator 130.

The gas turbine engine 150 may use natural gas, various types of syngas, liquid fuels, and/or other types of fuels and blends thereof. The gas turbine engine 150 may have different configurations and may use other types of components. Other types of gas turbine engines may also be used herein. Multiple gas turbine engines, other types of turbines, and other types of power generation equipment may also be used herein together.

The gas turbine 150 may also be coupled to a turbine controller 160. Turbine controller 160 may control one or more aspects of the operation of gas turbine 150. The generator 130 may be coupled to the exciter 120 controlled by the exciter controller 110. The exciter 120 may be configured to automatically regulate voltage and supply Direct Current (DC) output. For example, the exciter 120 may include circuitry that provides DC current and DC voltage to the field windings of the rotor of the generator 130, thereby inducing a magnetic field within the generator 130. The magnetic field may then cause the rotor to rotate inside the generator and rotate the shaft of the generator 130. In addition to generating a magnetic field within the generator 130, the exciter 120 may be used to control the frequency, amplitude, and phase characteristics of the voltage output by the generator 130. Thus, after the generator shaft is rotating at its rated speed, the exciter 120 may be used to synchronize the voltage output by the generator 130 with the voltage of the grid 140.

The exciter controller 110 can be a computing system that optionally includes one or more of an input interface 112, an output interface 118, one or more processors 114, and/or one or more memory devices 116. As described in detail below, under control of the power generation system 100, the exciter controller 110 facilitates identification of transient grid events. In an alternative embodiment, a controller separate from the exciter controller 110 may be used instead of or in addition to the exciter controller 110.

After a transient event on the grid 140 that causes a frequency deviation, the power generation system 100 may use the turbine controller 160 to bring the system back to equilibrium. For example, when a frequency drop in the grid 140 is detected, a speed drop may be detected, as the speed varies with the grid frequency. The fuel intake of the prime mover will increase based on sensing the speed drop, which increases the active power output to compensate for the frequency drop.

Turbine 150 may rotate a shaft in generator 130 such that generator 130 outputs a voltage. The voltage output of generator 130 may then be synchronized with the voltage of grid 140. In some embodiments, the exciter controller 110 may monitor electrical characteristics of the grid 140. Accordingly, exciter controller 120 may monitor grid 140 for transient events, such as a rise or fall in grid frequency, a rise or fall in active or reactive power of generator 130, and so forth. Transient events may include changes in electrical characteristics such as voltage, current, power factor, and the like.

In some embodiments, the exciter controller 120 may be configured to detect or identify a transient grid event at the initial stage of the grid transient to its occurrence. Upon detecting a transient event, the exciter controller 120 may send a command or notification to the turbine controller 160 to adjust the operation of the prime mover and compensate for the frequency change of the generator. That is, the exciter controller 120 may monitor electrical parameters of the generator 130, such as power output and electrical frequency, and detect transient events based on the electrical parameters.

The power generation system 100 described herein may provide fast load support in response to a grid frequency transient event via a combination of one or all of the following: (i) early electrical detection of a grid event; (ii) using the MW modeled value in place of the measured watt meter value (e.g., avoiding reading at the watt meter the power component contributed by the generator's kinetic energy in response to changes in frequency transients); and/or (iii) use of flexible dynamics for the fuel value control loop. Therefore, turbine response acceleration can be achieved without oscillating the turbine frequency. Further, in response to a decrease in the grid frequency, the instant electricity may be provided using, for example, aeroderivative gas turbines.

Fig. 2 is a schematic diagram of a control system for an exciter and gas turbine as may be described herein. Other embodiments may have additional, fewer, and/or different components or configurations than those discussed with respect to the example shown in fig. 2.

The control system shown in fig. 2 may be used to provide fast power in response to frequency events in a small grid or a grid that may be unstable. Some embodiments may use aeroderivative gas turbines with a fuel source such as diesel or ethanol.

In fig. 2, an Automatic Voltage Regulator (AVR)/exciter controller 200 may be configured to control operation of an exciter that provides DC voltage and/or DC current to the rotor of the generator. The AVR/exciter controller 200 may include one or more early electrical detection modules 202. The early electrical detection module 202 may be configured to detect a frequency drop in the electrical grid as a potential disturbance. For example, the early electrical detection module 202 may be configured to monitor one or more characteristics or electrical characteristics of the electrical grid, such as a frequency, voltage, current, power, or power factor associated with the electrical grid. Based on changes in grid characteristics or electrical characteristics, the early electrical detection module 202 may determine whether a transient event exists on the grid. For example, the early electrical detection module 202 may determine that a transient event is occurring or otherwise imminent if one or more of a frequency, voltage, current, power, or power factor associated with the electrical grid increases or decreases by more than a threshold. In one example, the AVR/exciter controller 200 may sense the rate of change of the electrical frequency at the terminals of the generator and may determine the rate of change of the axis acceleration (where the rate of change is one of the electrical characteristics monitored by the AVR/exciter controller 200) in order to determine whether a transient event is occurring. When a transient event is detected, the AVR/exciter controller 200 may send a notification 220 of the transient event to the turbine controller 210. Because the AVR/exciter controller 200 may be coupled to the generator and exciter, the AVR/exciter controller 200 may detect grid events faster and more reliably than speed measurement techniques.

The AVR/exciter controller 200 may communicate with the turbine controller 210. Turbine controller 210 may be configured to control the operation of a turbine, such as an aeroderivative gas turbine. Turbine controller 210 may receive notification 220 of a transient event from AVR/exciter controller 200. Turbine controller 210 may adjust the operation of the turbine based on notification 220. For example, the turbine controller 210 may adjust operation of the turbine based on modeled values of electrical power and/or based on dynamics of fuel demand to a fuel valve regulator of the turbine.

Upon receiving the notification 220 from the AVR/exciter controller 200, the turbine controller 210 may modify a first operating parameter 240 of the turbine by replacing a conventional dynamics 232 of the fuel demand of the fuel valve regulator of the turbine with an improved dynamics 230 of the fuel demand of the fuel valve regulator of the turbine. The dynamic override may adjust the first operating parameter 240 to increase or decrease fuel in response to a detected event. The first operating parameter 240 may be modified due to the notification 220. The dynamic replacement may be temporary to handle the event, and may return to normal operation after the event has passed. The flexible dynamics of the fuel valve control loop also ensures fast response without compromising stability.

In some embodiments, in addition to or instead of modifying the fuel dynamics, the turbine controller 210 may adjust the second operating parameter 284 in response to the notification 220. The second operating parameter 284 will be a measurement of the generator's electrical power. Due to the rotational inertia of the rotating machine coupled to the generator, the rotating machine gains kinetic energy as its rotational speed increases. When a grid transient occurs that results in a change in rotational speed, the kinetic energy also changes. The rate of change of kinetic energy causes a component of electrical output (and/or input), referred to as the inertial response, which is superimposed on a component of the electrical output of the generator produced by the working fluid of the turbine (e.g., the observed power increase, but not due to the fuel increase in the combustor). For example, a negative grid frequency transient event on a high inertia machine running at constant power demand will result in a larger positive inertia response that will increase power feedback, thereby introducing a larger negative error to the fuel regulator, such that the fuel regulator erroneously reduces fuel when the desired response of the frequency drop is to increase fuel to increase power to restore the system frequency. To this end, a turbine controller that adjusts fuel flow to the regulator 270 according to the error 260 between the power demand 250 and the power feedback 290 may have an improved response through an electrical transient event by using a switching feedback mechanism 284 that may select between measured power 282 or a modeled power output 280 that may not include an inertial response if it is known and detected that the event 220 would result in an undesirable fuel regulator response. Thus, turbine controller 210 may replace the MW value 282 measured by the wattmeter with MW modeled value 280. The substitution of values may adjust the second operating parameter 284 to increase or decrease fuel in response to the detected event. The replacement of values may be temporary to cope with the event, and may return to normal operation after the event has passed.

In some embodiments, turbine controller 210 may generate or determine MW modeled value 280. For example, the turbine controller 210 may determine the MW modeled value 280 based on the gas turbine high pressure compressor discharge pressure. By using the MW modeled value 280, the turbine controller 210 may avoid reading the inertial response at the wattmeter when a grid event occurs. In some cases, MW modeled value 280 may be calculated internally by turbine controller 210 based on variable geometry position and fuel demand.

The first operating parameter 240 may be fed to a MW demand module 250 at the turbine controller 210, which may be used to control operation of the valve 260. Similarly, the second operating parameter 284 may be fed to the MW feedback module 290 at the turbine controller 210, which may also be used to control the operation of the valve 260. Valve 260 may be used to supply fuel to fuel regulator 270 to operate the turbine.

Thus, the turbine controller 210 may be configured to generate a modeled value of electrical power, where the modeled value is a megawatt modeled value generated based on a compressor discharge pressure of a compressor at the turbine. The modeled values may temporarily replace the actual generator power readings at the wattmeter of the turbine. Further, the turbine controller 210 may be configured to adjust a dynamics of a fuel demand to a fuel valve regulator of the turbine, wherein the dynamics of the fuel demand is a flexible dynamics, and wherein the dynamics of the fuel demand may be adjusted by temporarily replacing the first dynamics with the second dynamics. The second dynamics may result in a controlled acceleration of the turbine. In some embodiments, the turbine controller 210 may also be configured to determine grid frequency boundaries and increase the valve response time to avoid oscillations in the turbine frequency response. Some embodiments may be configured such that the fuel actuator of the turbine reaches 95% of movement between the initial position and the final position at a minimum point frequency of about 4s (49Hz) at a nominal frequency of 50 Hz.

Thus, the control system ensures the reliability of turbine response to frequency events under severe grid conditions and does not use traditional speed control. Turbine controller 210 may activate controlled acceleration of the turbine in response to notification 220 through flexible dynamics of fuel valve control and without affecting stability. Embodiments of the present disclosure may adjust one or more operations of the turbine based on the modeled value of the power, where the one or more operations include a dominant frequency algorithm and dynamics to the fuel demand of the valve regulator. Thus, immediate power can be provided when a drop in the main grid frequency is detected.

Fig. 3 is an exemplary process flow 300 for fast load support for grid frequency transient events as may be described herein. One or more of the operations described in fig. 3 may be performed in a different order and/or by different computer systems in the same computer system or distributed computing environment. In one example, the operations of fig. 3 may be performed by the AVR/exciter controller 200 of fig. 2.

At block 310, a first controller (such as the AVR/exciter controller 200) may monitor a first set of electrical characteristics associated with the power grid. For example, the first controller may monitor frequency, voltage, current, power factor, and/or other electrical characteristics associated with the power grid.

At determination block 320, a determination may be made by the first controller as to whether there is a sudden change in the grid frequency. For example, the first controller 210 may determine whether one or more characteristics of the grid, such as the grid frequency, suddenly increases or decreases by more than a threshold amount. If it is determined at determination block 320 that there is no sudden change in the grid frequency, process flow 300 may return to block 310 and monitoring may continue using the first controller. If it is determined at determination block 320 that there is a sudden change in the grid frequency, process flow 300 may proceed to block 330.

At block 330, the first controller may determine that a transient event exists on the electrical grid based on the first set of electrical characteristics. For example, the first controller may determine that a transient event exists on the grid based on the grid frequency changing more than a threshold amount over a length of time.

At block 340, the first controller may send a notification of the transient event to the second controller. For example, the first controller may send a notification of the transient event to the turbine controller.

At block 350, the first controller may activate controlled acceleration of the turbine. In some embodiments, the first controller may activate the controlled acceleration of the turbine by causing the second controller to activate the controlled acceleration of the turbine. Controlled acceleration may reduce the risk of power loss due to rapid changes in the grid frequency.

Fig. 4 is an exemplary process flow 400 for fast load support for grid frequency transient events as may be described herein. One or more of the operations described in fig. 4 may be performed in a different order and/or by different computer systems in the same computer system or distributed computing environment. In one example, the operations of FIG. 4 may be performed by the turbine controller 210 of FIG. 2.

At block 410, a turbine controller of a turbine may receive notification of a transient event. For example, the AVR/exciter controller may detect transient events at the generator and/or the grid, and the turbine controller may receive notification of the transient events from the AVR/exciter controller.

At block 420, the turbine controller may determine the MW modeled value to replace the measured wattage value based on the compressor discharge pressure of the compressor at the turbine. For example, the turbine controller may cause, at least temporarily, the measured wattage meter value to be replaced with the MW modeled value. The MW modeling value may be determined based on a compressor discharge pressure of the compressor at the turbine and may reflect a transient event.

At block 430, the turbine controller may determine an improved dynamic fuel value for the fuel demand. The improved dynamic fuel value may be used at least temporarily in place of the conventional dynamics.

At block 440, the turbine controller may adjust the fuel demand using the improved dynamic value. For example, the turbine controller may adjust the dynamics of the fuel demand on the fuel valve regulator of the turbine.

At optional block 450, the turbine controller may adjust a main frequency algorithm for operating the turbine.

Thus, the turbine controller may allow the gas turbine to operate with multiple fuels and provide a fast response when a grid event occurs, and may provide improved control of the fuel supply valve when controlled acceleration of the turbine is required.

It should be apparent that the foregoing relates only to certain embodiments of the present application and the resultant patent. Many changes and modifications may be made herein by one of ordinary skill in the art without departing from the general spirit and scope of the invention as defined by the following claims and the equivalents thereof.