Electric transmission control method for electric locomotive for improving net pressure and electric locomotive

Abstract

The present disclosure provides a power locomotive electric transmission control method and a power locomotive for improving the grid pressure, the control method comprising: S1: obtaining the unit length impedance value of the power grid and the real-time operation parameters of the power locomotive; S2: calculating the reactive power compensation value of the power grid in real time through the unit length impedance value of the power grid and the real-time operation parameters of the power locomotive; S3: inputting the reactive power compensation value of the power grid into the four-quadrant rectifier of the power locomotive, and adjusting the control strategy of the four-quadrant rectifier of the power locomotive to compensate the reactive power of the power grid in real time. The present disclosure realizes real-time reactive compensation of the power grid by combining the impedance value of the power grid and the real-time operation parameters of the power locomotive, improves the stability of the power system and the energy utilization rate; without additional installation of equipment, the cost and complexity of the power grid reactive compensation system are reduced; through real-time monitoring and cooperative control, the required reactive compensation for the power system can be accurately provided.

Description

Technical Field

[0001] This disclosure relates to the field of electric locomotive transmission technology, and in particular to an electric locomotive transmission control method and an electric locomotive for improving grid voltage. Background Technology

[0002] With the rapid development of my country's rail transit industry, rail trains have placed higher demands on the stability of the overhead contact line voltage of electrified railways. The four-quadrant rectifier is an important component of the electric locomotive's electric drive system. In traction mode, it converts AC power from the traction transformer into DC power to provide energy to the intermediate circuit; in regenerative braking mode, it performs DC-AC conversion through the intermediate DC circuit to feed energy back to the power grid.

[0003] To improve the power factor at the pantograph and reduce harmonic currents in the overhead contact line, existing four-quadrant rectifiers are controlled with a power factor of "1" as the target. This control strategy can effectively compensate for the reactive power generated by the locomotive itself, thereby mitigating the reactive power impact on the power grid. However, in reality, the power grid supply system contains nonlinear loads and inductive components, and the grid itself also generates a certain amount of reactive power. This reactive power will cause additional current in the transmission lines, leading to increased line losses. Especially when multiple electric locomotives are running simultaneously, it may cause the voltage of the terminal contact line to be too low, limiting the power output of the electric locomotives and affecting operating efficiency. It may even cause the power supply system to trip, resulting in train stalling or even stopping, adversely affecting traffic order and transportation safety.

[0004] In existing technologies, the four-quadrant rectifiers of electric locomotives are mainly used to compensate for the reactive power generated by the locomotive itself, thereby reducing its impact on the power grid. However, existing methods struggle to compensate for the reactive power generated by the power grid itself because electric locomotives cannot accurately obtain real-time parameters of the power grid. Therefore, existing technologies for reactive power compensation typically employ specialized equipment and technologies, such as Static Var Compensators (SVCs), Dynamic Var Compensators (DVCs), or Flexible AC Transmission Systems (FACTS). These devices and technologies can adjust the compensation amount in real time according to the actual needs of the power grid, improving the power factor of the grid itself and enhancing the stability and reliability of the power system. However, the investment and maintenance costs of these reactive power compensation devices (SVCs, DVCs, and FACTS) are high, placing a significant economic burden on power companies and users. Furthermore, the operation of these reactive power compensation devices is complex, requiring specialized knowledge and skills for design, installation, and maintenance, increasing labor costs and workload.

[0005] Based on the above problems, how to achieve real-time reactive power compensation to the power grid by adjusting the control strategy of electric locomotives, so as to further improve the stability and reliability of the electric locomotive's power system, is a problem that needs to be solved by those in this technical field. Summary of the Invention

[0006] To address the aforementioned technical problems, one aspect of this disclosure provides a method for controlling the electric transmission of an electric locomotive to improve grid voltage, comprising:

[0007] S1: Obtain the impedance value per unit length of the power grid and the real-time operating parameters of the electric locomotive;

[0008] S2: Calculate the reactive power compensation value of the power grid in real time by using the impedance value per unit length of the power grid and the real-time operating parameters of the electric locomotive;

[0009] S3: Input the reactive power compensation value of the power grid to the four-quadrant rectifier of the electric locomotive, and adjust the control strategy of the four-quadrant rectifier of the electric locomotive to perform reactive power compensation on the power grid in real time.

[0010] Furthermore, S3 includes: when the reactive power compensation value of the power grid is greater than the compensation capacity of the electric locomotive, the electric locomotive compensates according to its maximum capacity; when the reactive power compensation value of the power grid is less than or equal to the compensation capacity of multiple electric locomotives, the electric locomotive compensates according to the reactive power compensation value of the power grid.

[0011] Furthermore, the control strategy includes time-sharing operation and dynamic scheduling of multiple electric locomotives.

[0012] Furthermore, dynamic dispatching includes: electric locomotives with large loads and low pantograph voltage do not provide reactive power compensation to the grid, while electric locomotives with low loads or high grid voltage at the front end of the grid provide reactive power compensation to the grid.

[0013] Furthermore, the control strategy also includes a power battery coordination mechanism, which involves the power battery of the electric locomotive coordinating with the four-quadrant rectifier to provide reactive power compensation to the power grid.

[0014] Furthermore, S3 also includes: monitoring the reactive power compensation effect of electric locomotives on the power grid through monitoring devices.

[0015] Furthermore, the control strategy adjustment instructions are issued by the power system control center and transmitted to the electric locomotive via a communication link.

[0016] Furthermore, current and voltage sensors installed at power stations or along the power grid are used to collect grid current and voltage in real time and transmit them to the power system control center via a communication link for calculating the grid impedance per unit length.

[0017] Furthermore, operating parameter sensors installed on the electric locomotive collect the locomotive's operating parameters in real time and transmit them to the power system control center via a communication link to calculate the reactive power compensation value required by the power grid.

[0018] Another aspect of this disclosure provides an electric locomotive, including: employing the above-described electric locomotive electric drive control method for improving grid voltage to perform reactive power compensation on the power grid.

[0019] According to the above technical solution, the present invention provides an electric locomotive electric transmission control method and an electric locomotive for improving grid voltage. The control method achieves real-time reactive power compensation of the grid by combining the grid impedance value and the real-time operating parameters of the electric locomotive, thereby improving the stability and energy utilization rate of the power system. It eliminates the need for additional equipment installation, reducing the cost and complexity of the grid reactive power compensation system. Through real-time monitoring and coordinated control, it can accurately provide the required reactive power compensation to the power system, thereby improving the stability and reliability of the power system. Furthermore, by controlling the power output and charge / discharge status of the power battery, it maintains grid stability while improving energy utilization efficiency. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this disclosure or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a flowchart of the control method disclosed in an embodiment of the present invention. Detailed Implementation

[0022] The embodiments of this disclosure will be further described in detail below with reference to the accompanying drawings and examples. The detailed description of the embodiments and the accompanying drawings are used to illustrate the principles of this disclosure by way of example, but should not be used to limit the scope of this disclosure. This disclosure can be implemented in many different forms and is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

[0023] These embodiments are provided to make the disclosure thorough and complete, and to fully express the scope of the disclosure to those skilled in the art. It should be noted that, unless otherwise specifically stated, the relative arrangement of components and steps, material composition, numerical expressions, and values ​​set forth in these embodiments should be interpreted as exemplary only and not as limiting.

[0024] It should be noted that, in the description of this disclosure, unless otherwise stated, "a plurality of" means two or more; the terms "upper," "lower," "left," "right," "inner," and "outer," etc., indicating orientation or positional relationship, are only for the convenience of describing this disclosure and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this disclosure. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0025] Furthermore, the terms "first," "second," and similar terms used in this disclosure do not indicate any order, quantity, or importance, but are merely used to distinguish different parts. "Vertical" is not strictly vertical, but within the permissible margin of error. "Parallel" is not strictly parallel, but within the permissible margin of error. Terms such as "including" or "contains" mean that the element preceding the word encompasses the element listed after the word, and do not exclude the possibility of encompassing other elements as well.

[0026] It should also be noted that, in the description of this disclosure, unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this disclosure depending on the specific circumstances. When a particular device is described as being located between a first device and a second device, an intermediary device may or may not be present between the particular device and the first or second device.

[0027] All terms used in this disclosure have the same meaning as understood by one of ordinary skill in the art to which this disclosure pertains, unless otherwise specifically defined. It should also be understood that terms defined in general dictionaries should be interpreted as having meanings consistent with their meanings in the context of the relevant art, and not as idealized or highly formalized, unless expressly defined herein.

[0028] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, they should be considered part of the specification.

[0029] As mentioned in the background section, the power grid supply system of electric locomotives contains nonlinear loads and inductive components, and the power grid itself also generates a certain amount of reactive power. This reactive power causes additional current in the transmission lines, leading to increased line losses. Especially when multiple electric locomotives are running simultaneously, the voltage of the terminal contact network may be too low, limiting the power output of the electric locomotives and affecting operating efficiency. It may even cause the power supply system to trip, resulting in train stalling or even stopping, adversely affecting traffic order and transportation safety. If reactive power compensation equipment is used to compensate for reactive power in the power grid, the investment and maintenance costs are high, placing a significant economic burden on power companies and users. Therefore, the inventors of this application provide an electric locomotive electric drive control method and electric locomotive for improving grid voltage in one or more embodiments, which is believed to solve one or more problems in the prior art. At the same time, those skilled in the art will also understand that the technical solution of this invention is also applicable to trains such as high-speed railways and EMUs that use AC contact network power supply.

[0030] To address the aforementioned technical problems, one aspect of the present invention provides a method for controlling the electric transmission of electric locomotives to improve grid voltage, such as... Figure 1 As shown, the control method consists of the following steps: S1: Obtain the unit length impedance value of the power grid and the real-time operating parameters of the electric locomotive; S2: Calculate the reactive power compensation value of the power grid in real time using the unit length impedance value of the power grid and the real-time operating parameters of the electric locomotive; S3: Input the reactive power compensation value of the power grid into the four-quadrant rectifier of the electric locomotive, and adjust the control strategy of the four-quadrant rectifier of the electric locomotive to perform reactive power compensation of the power grid in real time.

[0031] Specifically, the control system includes a power system control center and a communication link. First, the power system control center acquires the grid impedance per unit length and the locomotive's real-time operating parameters, and calculates the reactive power compensation value of the grid based on these parameters. Further, the reactive power compensation value can be calculated by establishing a mathematical model. The locomotive's real-time operating parameters include the locomotive load, voltage, pantograph distance from the power station, and speed. The model can be implemented using either online calculation or offline prediction, depending on the specific requirements. Then, the power system control center sends the calculated reactive power compensation value to the electric locomotive via the communication link. Upon receiving the reactive power compensation value, the electric locomotive performs reactive power compensation on the grid according to the four-quadrant rectifier control strategy.

[0032] Compared with existing technologies, the present invention provides an electric locomotive electric drive control method for improving grid voltage. By combining the grid impedance value and the real-time operating parameters of the electric locomotive, it achieves real-time reactive power compensation for the grid, thereby improving the stability and energy utilization rate of the power system.

[0033] In some embodiments, such as Figure 1 As shown, S3 further includes: when the reactive power compensation value of the power grid is greater than the compensation capacity of the electric locomotive, the electric locomotive compensates at its maximum capacity; when the reactive power compensation value of the power grid is less than or equal to the compensation capacity of multiple electric locomotives, the electric locomotive compensates according to the reactive power compensation value of the power grid. Compensating the reactive power of the power grid according to the compensation capacity of the electric locomotive ensures the normal operation of the electric locomotive while improving energy utilization efficiency.

[0034] In some embodiments, the control strategy includes time-sharing operation and dynamic scheduling of multiple electric locomotives. Specifically, a communication and coordination mechanism is established between the four-quadrant rectifiers of multiple electric locomotives. By coordinating the operating status of each locomotive and the control strategy of the four-quadrant rectifiers, reactive power compensation of the power grid can be achieved. Through real-time communication and data exchange, coordination and optimization between devices can be realized, avoiding mutual interference and over-compensation. Load balancing and optimization are also achieved among multiple electric locomotives to ensure the stability and efficiency of the entire power grid, realizing an overall energy management system that performs real-time control of electric locomotives throughout the power grid, optimizing the energy consumption and power factor of the entire power grid. Furthermore, the control strategy enables electric locomotives to obtain the power factor of the power grid provided by the power supply station in real time. Combined with the power factor calculated by the electric locomotive itself using impedance per unit length, the corresponding reactive power compensation is checked and optimized.

[0035] In some embodiments, dynamic scheduling includes: electric locomotives with high loads and low pantograph voltage do not receive reactive power compensation from the grid; electric locomotives with low loads or high grid voltage at the grid front end receive reactive power compensation from the grid. To adapt to different operating scenarios of electric locomotives of varying sizes, this invention can employ a multi-level control strategy, dynamically adjusting the control strategy based on factors such as grid load and the number of electric locomotives. Specifically, multiple control priorities can be set. For electric locomotives with high loads and low pantograph voltage, grid power compensation may not be performed, prioritizing their own needs. For low-load locomotives or locomotives with high grid voltage at the grid front end, grid reactive power compensation is performed, thereby ensuring the stable operation of the entire system.

[0036] In some embodiments, the control strategy further includes a power battery coordination mechanism, which involves the electric locomotive's power battery coordinating with a four-quadrant rectifier to compensate for reactive power in the power grid. Specifically, energy storage devices such as power batteries and supercapacitors can be integrated into the electric locomotive to work in conjunction with the four-quadrant rectifier, achieving reactive power compensation for the power grid. When the power grid requires reactive power compensation, these energy storage devices can provide active power to the grid while simultaneously compensating for reactive power, thereby increasing grid voltage. Energy is recovered during electric locomotive braking and stored in energy storage devices. When needed, the recovered energy is reintroduced into the grid, reducing the burden on the grid and preventing multiple electric locomotives from simultaneously feeding energy back to the grid, which could lead to excessively high grid voltage.

[0037] In some embodiments, S3 further includes: monitoring the reactive power compensation effect of the electric locomotives on the power grid through a monitoring device. By monitoring the actual reactive power compensation effect, the control strategy is dynamically adjusted to achieve more accurate reactive power compensation. Specifically, parameters such as voltage and current of the power system can be acquired in real time and compared with predicted values ​​to optimize the control strategy based on the actual situation. Furthermore, the power system control center evaluates the reactive power compensation effect based on real-time monitoring data. Based on the evaluation results, the control strategy can be further adjusted and the collaborative work of multiple electric locomotives can be coordinated to achieve a better reactive power compensation effect.

[0038] In some embodiments, control strategy adjustment commands are issued by the power system control center and transmitted to the electric locomotives via a communication link. Specifically, the power system control center monitors and analyzes data from the electric locomotives in real time, and calculates the reactive power compensation required by each electric locomotive based on the reactive power demand of the power grid and the actual operating conditions of the locomotives. The power system control center sends the calculated reactive power compensation requirements to the electric locomotives via the communication link. After receiving the requirements, the locomotives adjust their reactive power compensation levels according to their own four-quadrant rectifier control strategies. Furthermore, the power control center can adopt a distributed control system or a centralized control system to achieve coordinated reactive power compensation to the power grid in the case of multiple locomotives; the communication link connects the electric locomotives and the power system using real-time, high-speed, and bidirectional communication methods, specifically wireless or wired connections, such as local area networks, Bluetooth, and Wi-Fi.

[0039] In some embodiments, current and voltage sensors installed at power stations or along the power grid collect grid current and voltage in real time, and transmit them to the power system control center via a communication link for calculating the grid impedance per unit length.

[0040] In some embodiments, operating parameter sensors installed on electric locomotives collect the operating parameters of the electric locomotives in real time and transmit them to the power system control center via a communication link for calculating the reactive power compensation value required by the power grid.

[0041] On the other hand, the present invention also provides an electric locomotive, including an electric locomotive electric drive control method for improving grid voltage as described above to compensate for reactive power in the power grid.

[0042] In summary, compared with existing technologies, the electric locomotive transmission control method and electric locomotive provided by this invention for improving grid voltage achieve real-time reactive power compensation of the grid by combining grid impedance values ​​and real-time operating parameters of the electric locomotive, thereby improving the stability and energy utilization efficiency of the power system. It eliminates the need for additional equipment installation, reducing the cost and complexity of the grid reactive power compensation system. Through real-time monitoring and coordinated control, it can accurately provide the required reactive power compensation to the power system, thereby improving the stability and reliability of the power system. Furthermore, by controlling the power output and charge / discharge status of the power battery, it maintains grid stability while improving energy utilization efficiency.

[0043] The embodiments of this disclosure have now been described in detail. To avoid obscuring the concept of this disclosure, some details known in the art have not been described. Those skilled in the art can fully understand how to implement the technical solutions disclosed herein based on the above description.

[0044] While specific embodiments of this disclosure have been described in detail by way of examples, those skilled in the art should understand that the examples are for illustrative purposes only and not intended to limit the scope of this disclosure. Those skilled in the art should understand that modifications can be made to the above embodiments or equivalent substitutions can be made to some technical features without departing from the scope and spirit of this disclosure. In particular, as long as there is no structural conflict, the technical features mentioned in the various embodiments can be combined in any manner.

Claims

1. A method of electric transmission control for an electric locomotive for improving the tractive effort, characterized by, include: S1: Obtain the impedance value per unit length of the power grid and the real-time operating parameters of the electric locomotive; S2: Calculate the reactive power compensation value of the power grid in real time using the unit length impedance value of the power grid and the real-time operating parameters of the electric locomotive; S3: Input the reactive power compensation value of the power grid to the four-quadrant rectifier of the electric locomotive, and adjust the control strategy of the four-quadrant rectifier of the electric locomotive to perform reactive power compensation on the power grid in real time. S3 includes: when the reactive power compensation value of the power grid is greater than the compensation capacity of the electric locomotive, the electric locomotive compensates according to its maximum capacity; when the reactive power compensation value of the power grid is less than or equal to the compensation capacity of multiple electric locomotives, the electric locomotive compensates according to the reactive power compensation value of the power grid. The control strategy includes time-sharing operation and dynamic scheduling of multiple electric locomotives; The dynamic scheduling includes: electric locomotives with large loads and low pantograph voltage will not receive reactive power compensation from the power grid, while electric locomotives with low loads or high voltage at the front end of the power grid will receive reactive power compensation from the power grid.

2. The electric locomotive transmission control method for improving grid voltage according to claim 1, characterized in that, The control strategy also includes a power battery coordination mechanism, which includes: the power battery of the electric locomotive and the four-quadrant rectifier working together to compensate the power grid for reactive power.

3. The electric locomotive transmission control method for improving grid voltage according to claim 1, characterized in that, The S3 further includes: monitoring the reactive power compensation effect of the electric locomotive on the power grid through a monitoring device.

4. The electric locomotive transmission control method for improving grid voltage according to claim 1, characterized in that, The control strategy adjustment command is issued by the power system control center and transmitted to the electric locomotive via a communication link.

5. The electric locomotive transmission control method for improving grid voltage according to claim 4, characterized in that, Current and voltage sensors installed at power stations or along the power grid are used to collect the current and voltage of the power grid in real time, and transmit them to the power system control center via the communication link for calculating the impedance value per unit length of the power grid.

6. The electric locomotive transmission control method for improving grid voltage according to claim 5, characterized in that, Operating parameter sensors installed on the electric locomotive collect the locomotive's operating parameters in real time and transmit them to the power system control center via the communication link for calculating the reactive power compensation value required by the power grid.

7. An electric locomotive, characterized in that, include: The electric locomotive electric drive control method for improving grid voltage according to any one of claims 1-6 is used to perform reactive power compensation on the power grid.

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