Method and system for coordinating configuration of high voltage direct current frequency control and emergency power control

Abstract

The present application relates to the technical field of high-voltage direct-current operation control, and particularly relates to a high-voltage direct-current frequency control and emergency power control coordination configuration method and system, comprising obtaining a current operation power instruction and a direct-current system frequency control adjustment amount; obtaining a direct-current frequency controller starting value according to the direct-current system frequency control adjustment amount; obtaining a direct-current emergency power modulation instruction, and determining a direct-current emergency power control starting value according to the direct-current emergency power modulation instruction; starting a direct-current power coordination control mechanism according to the direct-current frequency controller starting value and the direct-current emergency power control starting value; updating the current operation power instruction according to a delay stage frequency controller adjustment amount and the direct-current emergency power modulation instruction to obtain a direct-current system operation power update instruction; and completing direct-current active power modulation according to the direct-current system operation power update instruction. The present application realizes dynamic coordination control of high-voltage direct-current power transmission system power and frequency, and ensures safe and reliable operation of a power grid.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high-voltage direct-current operation control, and particularly relates to a high-voltage direct-current frequency control and emergency power control coordination configuration method and system. BACKGROUND

[0002] In a power system, there is a significant mismatch between the geographical distribution of energy resources and power consumption demand. Specifically, abundant coal, water power, wind power and solar power resources are mainly concentrated in remote areas, while power load centers are mainly concentrated in economically developed and densely populated urban areas. This uneven distribution of resources promotes the development of cross-regional direct-current transmission technology to achieve the optimal allocation and long-distance transmission of power resources. At present, large regional power grids have realized power transmission and interconnection between regions through cross-regional direct-current asynchronous interconnection technology. Among them, the direct-current transmission system plays an important role in the power system due to its rapid controllability. It can provide frequency and power support by adjusting the direct-current operating power according to the operating requirements of the alternating-current system. The active power control of the direct-current system mainly includes frequency control and emergency power control. The direct-current frequency controller calculates and adjusts the direct-current power in real time to maintain the frequency stability of the power system by detecting the change of the converter bus frequency.

[0003] However, although the two control means of the active power control of the direct-current system both act on the operating power of the direct-current transmission, their driving mechanisms and positions in the power system are different. In actual operation, the two may simultaneously adjust the direct-current operating power, which leads to a conflict between the control targets. For example, when a large disturbance occurs in the receiving end alternating-current system of the direct current, the control system starts the direct-current emergency power control to reduce the direct-current operating power. At this time, the sending end alternating-current system of the direct current causes the system frequency to rise due to power surplus, triggering the direct-current frequency controller to act to increase the direct-current power, thereby weakening the effect of the emergency power control and even endangering the stability of the receiving end alternating-current system.

[0004] Therefore, how to effectively coordinate the functions of the direct-current frequency controller and the emergency power control to avoid the contradiction between the adjustment requirements of the direct-current power when the two simultaneously act, and ensure that the direct-current system can provide sufficient and appropriate active power regulation for the alternating-current system under power system disturbance, thereby maintaining the safe and stable operation of the entire power system, is a problem that needs to be solved at present. SUMMARY

[0005] To solve the above technical problems, the present application provides a high-voltage direct-current frequency control and emergency power control coordination configuration method and system.

[0006] In a first aspect, the present application provides a high-voltage direct-current frequency control and emergency power control coordination configuration method, which comprises the following steps:

[0007] initial state flag of the high voltage direct current transmission system; the initial state flag comprises a direct current emergency power control starting initial value and a direct current frequency controller starting initial value;

[0008] According to the current direct current operating state of the high voltage direct current transmission system, the current operating power instruction and the direct current system frequency control adjustment amount of the high voltage direct current transmission system are obtained;

[0009] According to the direct current system frequency control adjustment amount and the preset direct current frequency control action threshold value, the direct current frequency controller starting value is obtained;

[0010] The direct current emergency power modulation instruction is calculated according to the system disturbance monitoring data, and the direct current emergency power control starting value is determined according to the direct current emergency power modulation instruction;

[0011] The direct current power coordination control mechanism is started according to the direct current frequency controller starting value and the direct current emergency power control starting value, and the delay stage frequency controller adjustment amount is determined according to the working state of the direct current power coordination control mechanism;

[0012] The current operating power instruction is updated according to the delay stage frequency controller adjustment amount and the direct current emergency power modulation instruction, and the direct current system operating power update instruction is calculated;

[0013] The high voltage direct current transmission system is controlled to operate according to the direct current system operating power update instruction, and the direct current active power modulation is completed.

[0014] In further embodiments, the step of obtaining the current operating power instruction and the direct current system frequency control adjustment amount according to the current direct current operating state of the high voltage direct current transmission system comprises:

[0015] The direct current voltage data and the direct current current data of the high voltage direct current transmission system are collected, and the current direct current power is calculated according to the direct current voltage data and the direct current current data;

[0016] The current operating power instruction of the high voltage direct current transmission system is determined according to the power system dispatching demand, the current direct current power and the rated power of the high voltage direct current transmission system;

[0017] The alternating current system frequency measurement data is collected, and the alternating current system frequency measurement data is compared with the preset frequency reference value to calculate the frequency deviation;

[0018] The frequency control adjustment amount is calculated by using a proportional integral controller according to the frequency deviation.

[0019] In further embodiments, the step of determining a DC frequency controller start value based on the DC system frequency control adjustment and a preset DC frequency control action threshold comprises:

[0020] comparing the DC system frequency control adjustment with the DC frequency control action threshold, and if the DC system frequency control adjustment exceeds the DC frequency control action threshold, determining that the DC frequency controller starts prior to the emergency power control, and setting the DC frequency controller start value to one;

[0021] if the DC system frequency control adjustment does not exceed the DC frequency control action threshold, determining that the emergency power control starts prior to the DC frequency controller, and setting the DC frequency controller start value to zero.

[0022] In further embodiments, the step of determining a DC emergency power control start value based on the DC emergency power modulation instruction comprises:

[0023] comparing an absolute value of the DC emergency power modulation instruction with a preset emergency power control action threshold, and if the absolute value of the DC emergency power modulation instruction is greater than the emergency power control action threshold, determining that the emergency power control is started, and setting the DC emergency power control start value to one;

[0024] if the absolute value of the DC emergency power modulation instruction is equal to the emergency power control action threshold, determining that the emergency power control is blocked, and setting the DC emergency power control start value to zero.

[0025] In further embodiments, the step of starting the DC power coordination control mechanism based on the DC frequency controller start value and the DC emergency power control start value comprises:

[0026] determining a start timing flag sum based on the sum of the DC frequency controller start value and the DC emergency power control start value;

[0027] multiplying the start timing flag sum with the DC emergency power control start value to obtain a DC power coordination control flag value, and starting the DC power coordination control mechanism based on the DC power coordination control flag value.

[0028] In further embodiments, the step of determining a delay phase frequency controller adjustment based on the working state of the DC power coordination control mechanism comprises:

[0029] when the DC power coordination control mechanism is started, setting the DC frequency controller start value as the delay phase frequency controller adjustment;

[0030] When the DC power coordination control mechanism is not working, the delay stage frequency controller adjustment amount is set to zero.

[0031] In a further embodiment, the step of updating the current operating power instruction according to the delay stage frequency controller adjustment amount and the DC emergency power modulation instruction comprises:

[0032] The current operating power instruction is added to the delay stage frequency controller adjustment amount and the DC emergency power modulation instruction to obtain a DC system operating power update instruction.

[0033] In a further embodiment, after the step of completing the DC active power modulation according to the DC system operating power update instruction, the method further comprises:

[0034] The delay time is determined according to the working state of the DC power coordination control mechanism, and after the delay time ends, the DC frequency controller is unlocked, the DC frequency controller and the emergency power control function are restored, and the HVDC power transmission system returns to a normal operating state.

[0035] In a further embodiment, the delay time is determined according to the DC frequency controller lock duration of different DC power coordination control mechanisms.

[0036] In a second aspect, the present application provides a high-voltage DC frequency control and emergency power control coordination configuration system, which comprises:

[0037] An initial state flag initialization module is configured to initialize an initial state flag of the HVDC power transmission system; the initial state flag comprises a DC emergency power control start initial value and a DC frequency controller start initial value.

[0038] An operating frequency analysis module is configured to obtain a current operating power instruction and a DC system frequency control adjustment amount of the HVDC power transmission system according to a current DC operating state of the HVDC power transmission system.

[0039] A frequency start analysis module is configured to obtain a DC frequency controller start value according to the DC system frequency control adjustment amount and a preset DC frequency control action threshold.

[0040] An emergency power control module is configured to obtain a DC emergency power modulation instruction according to system disturbance monitoring data, and determine a DC emergency power control start value according to the DC emergency power modulation instruction.

[0041] The time delay adjustment control module is used for starting a direct current power coordination control mechanism according to the direct current frequency controller starting value and the direct current emergency power control starting value, and determining a time delay stage frequency controller adjustment amount according to a working state of the direct current power coordination control mechanism.

[0042] The running power updating module is used for updating the current running power instruction according to the time delay stage frequency controller adjustment amount and the direct current emergency power modulation instruction, and calculating a direct current system running power updating instruction.

[0043] The power coordination control module is used for controlling the high voltage direct current power transmission system to run according to the direct current system running power updating instruction, and completing direct current active power modulation.

[0044] The application provides a high voltage direct current frequency control and emergency power control coordination configuration method and system, which comprises the following steps: initializing an initial state flag of a high voltage direct current power transmission system; obtaining a current running power instruction and a direct current system frequency control adjustment amount of the high voltage direct current power transmission system according to a current direct current running state of the high voltage direct current power transmission system; obtaining a direct current frequency controller starting value according to the direct current system frequency control adjustment amount and a preset direct current frequency control action threshold value; calculating a direct current emergency power modulation instruction according to system disturbance monitoring data, and determining a direct current emergency power control starting value according to the direct current emergency power modulation instruction; starting a direct current power coordination control mechanism according to the direct current frequency controller starting value and the direct current emergency power control starting value, and determining a time delay stage frequency controller adjustment amount according to a working state of the direct current power coordination control mechanism; updating the current running power instruction according to the time delay stage frequency controller adjustment amount and the direct current emergency power modulation instruction, and calculating a direct current system running power updating instruction; and controlling the high voltage direct current power transmission system to run according to the direct current system running power updating instruction, and completing direct current active power modulation. Compared with the prior art, the method flexibly adjusts the direct current power output according to the real-time state of the high voltage direct current power transmission system, realizes dynamic coordination control of the power and frequency of the high voltage direct current power transmission system, ensures that the system can quickly recover to a stable state when facing a disturbance, and effectively improves the stability and running efficiency of the system. BRIEF DESCRIPTION OF DRAWINGS

[0045] Figure 1 It is a high voltage direct current frequency control and emergency power control coordination configuration method flowchart provided by the embodiment of the application.

[0046] Figure 2 It is a high voltage direct current frequency control and emergency power control coordination configuration process block diagram provided by the embodiment of the application.

[0047] Figure 3is the effect comparison schematic diagram of the coordination configuration method of the DC frequency controller under the non-action working condition provided by the embodiment of the present application;

[0048] Figure 4 is the effect comparison schematic diagram of the coordination configuration method of the DC frequency controller under the action working condition provided by the embodiment of the present application;

[0049] Figure 5 is the system block diagram of the coordination configuration of the high-voltage DC frequency control and the emergency power control provided by the embodiment of the present application. DETAILED DESCRIPTION

[0050] The embodiments of the present application will be described in detail below with reference to the accompanying drawings. The embodiments are given only for illustrative purposes and cannot be understood as limiting the present application. The accompanying drawings are only for reference and illustration and do not constitute a limitation on the scope of patent protection of the present application, because many changes can be made to the present application without departing from the spirit and scope of the present application.

[0051] REFERENCE Figure 1 The embodiment of the present application provides a coordination configuration method of high-voltage DC frequency control and emergency power control, as shown in the figure, the method comprises the following steps: Figure 1

[0052] S1. Initialize the initial state flag bit of the high-voltage DC power transmission system; the initial state flag bit includes the initial value of the DC emergency power control start and the initial value of the DC frequency controller start.

[0053] S2. According to the current DC operating state of the high-voltage DC power transmission system, the current operating power instruction and the DC system frequency control adjustment amount of the high-voltage DC power transmission system are obtained.

[0054] In the embodiment, the step of obtaining the current operating power instruction and the DC system frequency control adjustment amount of the high-voltage DC power transmission system according to the current DC operating state of the high-voltage DC power transmission system comprises:

[0055] Collecting DC voltage data and DC current data of the high-voltage DC power transmission system, and calculating the current DC power according to the DC voltage data and the DC current data;

[0056] According to the power system dispatching demand, the current DC power and the rated power of the high-voltage DC power transmission system, the current operating power instruction of the high-voltage DC power transmission system is determined;

[0057] Collecting AC system frequency measurement data, and comparing the AC system frequency measurement data with the preset frequency reference value to calculate the frequency deviation;

[0058] According to the frequency deviation, the frequency control adjustment amount is calculated by using a proportional-integral controller.​

[0059] Specifically, such as Figure 2 As shown, in the control process of the high-voltage direct current (HVDC) transmission system, this embodiment defines two flag variables: DC emergency power control activation state and DC frequency controller activation state. Initially, this embodiment can set these two flag variables to 0 according to system design requirements and safe operation standards, indicating that the corresponding control functions are not activated. Then, this embodiment collects DC voltage data V and DC current data I of the HVDC transmission system in real time through sensors. Based on the collected DC voltage and DC current data, the current DC power P is calculated using the formula P = V × I. At the same time, the current required DC power dispatch demand value is obtained from the power system dispatch center. The current DC power is compared with the DC power dispatch demand value. If the current power is lower than the dispatch demand power, the power value that needs to be increased is calculated based on the system's regulation capacity and safety margin, and this value is added to the current power to obtain a new operating power command. If the current power is higher than the dispatch demand power, the power value that needs to be reduced is calculated and subtracted from the current power to obtain a new operating power command. The rated power limit of the HVDC transmission system is considered to ensure that the current operating power command does not exceed the rated power, thereby determining the current operating power command of the HVDC transmission system.

[0060] For the frequency control adjustment, this embodiment uses an AC system frequency measurement device to collect AC system frequency data in real time. The collected frequency data is compared with a preset frequency reference value to calculate the frequency deviation. Then, the parameters of the proportional-integral (PI) controller are set, including the proportional coefficient and the integral coefficient. The frequency deviation is input into the PI controller, and the frequency control adjustment is calculated according to the PI control algorithm. Specifically, the frequency deviation α is multiplied by the proportional coefficient K. p and integral coefficient K i Then, the results of the two are added together to obtain the frequency control adjustment amount. The specific formula is: Frequency Control Adjustment Amount Where t represents time.

[0061] S3. Based on the DC system frequency control adjustment amount and the preset DC frequency control action threshold, obtain the DC frequency controller start value.

[0062] In this embodiment, the step of obtaining the DC frequency controller start-up value based on the DC system frequency control adjustment amount and the preset DC frequency control action threshold includes:

[0063] comparing the direct current system frequency control adjustment amount and the direct current frequency control action threshold value, if the direct current system frequency control adjustment amount exceeds the direct current frequency control action threshold value, it is determined that the direct current frequency controller is started earlier than the emergency power control, and the direct current frequency controller starting value is set to 1;

[0064] If the direct current system frequency control adjustment amount does not exceed the direct current frequency control action threshold value, it is determined that the emergency power control is started earlier than the direct current frequency controller, and the direct current frequency controller starting value is set to 0.

[0065] In the power system, the direct current frequency control is one of the important means to maintain the stability of the system frequency, especially after the large-scale renewable energy access, the system frequency fluctuation is more frequent and severe, in order to effectively manage this fluctuation, the embodiment needs to determine the starting time of the direct current frequency controller according to the direct current system frequency control adjustment amount and the preset direct current frequency control action threshold value, specifically, the embodiment defines the direct current system frequency control adjustment amount as the amount that needs to be adjusted which is automatically calculated by the direct current system according to the current frequency deviation; the direct current frequency control action threshold value is used to judge whether the direct current frequency controller needs to be started, and the direct current frequency control action threshold value can generally be 0, the embodiment compares the obtained frequency control adjustment amount P FC of the direct current system with the preset direct current frequency control action threshold value ε, if |P FC |>ε, that is, the absolute value of the direct current system frequency control adjustment amount exceeds the preset direct current frequency control action threshold value, which indicates that the current frequency deviation of the system is large enough, and the direct current frequency controller needs to be immediately intervened to stabilize the system frequency, in this case, the embodiment determines that the direct current frequency controller is started earlier than the emergency power control, and sets the direct current frequency controller starting value D FC to 1, which indicates that the direct current frequency controller should be activated and put into operation, it should be noted that the emergency power control is usually used as the last line of defense of the system frequency, and is started when the direct current frequency controller cannot effectively stabilize the frequency; if |P FC |≤ε, that is, the direct current system frequency control adjustment amount does not exceed the preset direct current frequency control action threshold value, which indicates that the current frequency deviation of the system is still within an acceptable range, and the direct current frequency controller does not need to be started immediately, in this case, it is determined that the emergency power control is started earlier than the direct current frequency controller, and the direct current frequency controller starting value D FC is set to 0, which indicates that the direct current frequency controller does not need to be activated under the current condition, and its mathematical expression is:

[0066]

[0067] In the formula, when D FC =1, it indicates that the frequency controller is started earlier than the emergency power control; when DFC = 0, it means that the emergency power control is prior to the frequency controller to start.

[0068] The embodiment sends the corresponding start or standby state instruction to the DC frequency controller through the control system according to the set DC frequency controller start value. The embodiment ensures that the DC frequency controller starts at the appropriate time by continuously monitoring the frequency state of the system and the actual operation of the DC frequency controller, effectively supports the frequency stability control of the power system, and improves the reliability and safety of the system.

[0069] S4. Calculate the DC emergency power modulation instruction according to the system disturbance monitoring data, and determine the DC emergency power control start value according to the DC emergency power modulation instruction.

[0070] In the embodiment, the step of determining the DC emergency power control start value according to the DC emergency power modulation instruction comprises:

[0071] Comparing the absolute value of the DC emergency power modulation instruction with a preset emergency power control action threshold value, if the absolute value of the DC emergency power modulation instruction is greater than the emergency power control action threshold value, it is determined that the emergency power control is started, and the DC emergency power control start value is set to one.

[0072] If the absolute value of the DC emergency power modulation instruction is equal to the emergency power control action threshold value, it is determined that the emergency power control is blocked, and the DC emergency power control start value is set to zero.

[0073] The security control system obtains the real-time operation state of the system by real-time monitoring of the voltage, current and other electrical quantities of the system, and then calculates the DC emergency power modulation instruction P mod required for guaranteeing the safe and stable operation of the system according to the pre-set disturbance type (such as short-circuit fault, load mutation, etc.) and the transient stability constraint condition of the system by using the transient stability analysis method (such as time domain simulation method or direct method, etc.). mod Then, the embodiment determines the DC emergency power control start value D mod In the power system, the DC emergency power control is an important adjusting means, which is mainly used for rapidly adjusting the DC power transmission power to maintain the stable operation of the system when the system appears serious frequency deviation or power imbalance. The embodiment sets the emergency power control action threshold value to determine whether the DC emergency power control needs to be started. The embodiment sets the emergency power control action threshold value as 0 in priority, and then compares the absolute value of the calculated DC emergency power modulation instruction P mod with the preset emergency power control action threshold value T mod If |Pmod |>T mod If the absolute value of the DC emergency power modulation command is greater than the emergency power control action threshold, it indicates that the current system needs to urgently adjust the DC power to maintain stability. In this case, this embodiment determines to activate emergency power control, which will be based on P... mod The instruction adjusts the power output of the DC system, and simultaneously sets the DC emergency power control activation value D. mod Setting it to 1 indicates that emergency power control should be activated and put into operation; if |P mod |=T mod In other words, if the absolute value of the DC emergency power modulation command equals the emergency power control action threshold, it indicates that the system is currently at the critical point of emergency power control, but has not yet reached the point where emergency power control must be initiated. In this case, this embodiment determines to lock out emergency power control. Locking out means that even if an emergency power modulation command is issued, the system will not execute emergency power control action because the command value equals the threshold. Simultaneously, this embodiment sets the DC emergency power control activation value D... mod Setting it to 0 indicates that emergency power control does not need to be activated under the current conditions. The specific mathematical expression is:

[0074]

[0075] In the formula, when D mod When D = 1, it indicates that emergency power control is activated; when D mod When = 0, it indicates that the emergency power control is locked.

[0076] In this embodiment, based on the set DC emergency power control start value, the control system sends corresponding start or lockout commands to the DC emergency power control module, continuously monitors the power status of the system and the actual operation of the DC emergency power control module, and can ensure that the DC emergency power control starts or locks out at the appropriate time, effectively supporting the stable operation and power balance regulation of the power system.

[0077] S5. Activate the DC power coordination control mechanism according to the DC frequency controller activation value and the DC emergency power control activation value, and determine the frequency controller adjustment amount during the delay phase according to the working state of the DC power coordination control mechanism.

[0078] In this embodiment, the step of activating the DC power coordination control mechanism based on the DC frequency controller activation value and the DC emergency power control activation value includes:

[0079] The start-up timing flag is obtained by summing the DC frequency controller start-up value and the DC emergency power control start-up value;

[0080] The starting time sequence flag is multiplied by the DC emergency power control starting value to obtain a DC power coordination control flag value, and a DC power coordination control mechanism is started according to the DC power coordination control flag value.

[0081] The step of determining the delay stage frequency controller adjustment amount according to the working state of the DC power coordination control mechanism comprises:

[0082] When the DC power coordination control mechanism is started to work, the DC frequency controller starting value is assigned to the delay stage frequency controller adjustment amount.

[0083] When the DC power coordination control mechanism is not started to work, the delay stage frequency controller adjustment amount is set to zero.

[0084] In a specific embodiment, the DC frequency controller starting value and the DC emergency power control starting value are both binary variables, which are respectively used to indicate whether the DC frequency controller is started and whether the DC emergency power control is started. Specifically, the starting of the DC power coordination control mechanism is based on the starting working condition of the two types of strategies of the DC frequency controller and the DC emergency power control. When D FC = 1 and D mod = 1, that is, the DC frequency controller and the DC emergency power control have both been started, the DC power coordination control is started at this time. The setting of this determination condition is to ensure that the coordination measures are taken in time in the case of conflict between the two control strategies, to avoid unreasonable adjustment of the DC operating power, and to ensure the safe and stable operation of the power system. In this embodiment, the DC frequency controller starting value and the DC emergency power control starting value are added to obtain a starting time sequence flag sum, and then the starting time sequence flag sum is multiplied by the DC emergency power control starting value to obtain a DC power coordination control flag value. The mathematical expression is:

[0085] S cod = D mod × (D mod + D FC )

[0086] The embodiment starts the DC power coordination control mechanism only when at least one controller is started and the emergency power control is also started. If the emergency power control is not started, even if the frequency controller is started, we do not start the coordination control mechanism. The embodiment judges whether the DC power coordination control mechanism is started. If the DC power coordination control flag value is not zero, the DC power coordination control mechanism is started. If the DC power coordination control flag value is zero, the DC power coordination control mechanism is not started. When the DC power coordination control mechanism is started, the DC frequency controller starting value is assigned to the delay stage frequency controller adjustment. When the DC power coordination control mechanism is not started, the delay stage frequency controller adjustment is set to zero, which means that the frequency controller does not make any adjustment in the delay stage without the support of the DC power coordination control mechanism. The mathematical expression is:

[0087]

[0088] Meanwhile, the embodiment determines the delay time S according to the working state of the DC power coordination control mechanism delay :

[0089]

[0090] In the formula, NP FC is the delay stage frequency controller adjustment. When the DC power coordination control mechanism is started, it is used to represent the adjustment of the frequency controller in the delay stage. P FC is the frequency control adjustment of the DC system. S cod is the DC power coordination control flag value, which takes values 0, 1, 2, respectively, representing no coordination, coordination mode 1, and coordination mode 2. The value is determined according to the order of starting of the DC frequency controller and the emergency control and the current running state of the system. When D FC = 0 and D mod = 1, i.e., the emergency power control is started first. At this time, S cod = 0, no coordination control is performed, because the emergency power control is executed first and does not conflict with the frequency controller. When D FC = 1 and D mod = 1, the system frequency change trend and the emergency power control instruction size are further judged. If the system frequency rise trend is relatively flat and the power adjustment amount required by the emergency power control instruction is small, S cod = 1, coordination mode 1 is adopted. If the system frequency rise trend is fast and the power adjustment amount required by the emergency power control instruction is large, S cod = 2, coordination mode 2 is adopted. S delay is the delay time, which is represented as codThe determined DC frequency controller blocking duration time is determined according to the DC frequency controller blocking duration time of different DC power coordination control mechanisms; t1 and t2 are respectively the DC frequency controller blocking duration time corresponding to coordination mode 1 and coordination mode 2, which can be respectively taken as 1800s and 30s according to the system stability control demand.

[0091] According to the working state of the DC power coordination control mechanism, the embodiment adjusts the regulation amount of the delay stage frequency controller in real time, and monitors the frequency and power state of the system, thereby effectively supporting the frequency stability and power balance regulation of the power system.

[0092] S6. The current operation power instruction is updated according to the delay stage frequency controller regulation amount and the DC emergency power modulation instruction, and a DC system operation power update instruction is calculated.

[0093] In the embodiment, the step of updating the current operation power instruction according to the delay stage frequency controller regulation amount and the DC emergency power modulation instruction to calculate the DC system operation power update instruction comprises:

[0094] The current operation power instruction is added to the delay stage frequency controller regulation amount and the DC emergency power modulation instruction to obtain the DC system operation power update instruction.

[0095] Specifically, the embodiment adds the current operation power instruction P ref to the delay stage frequency controller regulation amount NP FC and the DC emergency power modulation instruction P mod to obtain the updated DC system operation power instruction NP ref , and the mathematical expression is:

[0096] NP ref = P ref + P mod + NP FC

[0097] The embodiment sends the calculated DC system operation power update instruction to the execution mechanism of the DC system, such as the control system of the DC converter station, to adjust the operation power of the DC system, monitor the actual operation power of the DC system, and compare it with the updated power instruction to ensure that the DC system operates correctly according to the instruction. If there is a deviation between the actual operation power and the instruction, the embodiment can further adjust the control strategy.

[0098] S7. The high-voltage direct-current power transmission system is controlled to operate according to the DC system operation power update instruction, and the DC active power modulation is completed.

[0099] Specifically, the embodiment calculates the DC system operating power update instruction NP ref After that, the power instruction is updated from the current operating power instruction P ref to the DC system operating power update instruction NP ref After the DC system receives the DC system operating power update instruction NP ref , it starts to adjust its output power to match the new instruction value, for example, adjusts the trigger angle of the converter, DC voltage, and other parameters to achieve fast and accurate regulation of power, completes the DC active power modulation, and then the embodiment clears the DC emergency power control start value D mod after the modulation is completed, clears the DC emergency power control start value D mod , which indicates that the emergency state has been lifted, and clears the DC power coordination control flag value S cod to prepare for the next emergency control, while clearing the delay phase frequency controller adjustment amount NP FC to avoid interference with subsequent control; after the delay ends, the DC frequency controller start value D FC is cleared to restore the normal function of the DC frequency controller, and its mathematical expression is:

[0100]

[0101] After the clearing operation, the embodiment needs to confirm that the relevant flag bits and status codes have been correctly cleared to ensure the consistency of the system state, and after the delay time S delay ends, the DC frequency controller is released from the lockout state through system operation, and after the lockout state is released, the DC frequency controller and emergency power control functions are gradually restored, and the HVDC power transmission system returns to normal operation. After the power modulation and clearing operation are completed, the next pre-delay time S delay can be waited for, which is used to ensure system stability and avoid the adverse effects of frequent control switching on the system. Through the above steps, the embodiment can ensure that the HVDC power transmission system operates stably according to the new power instruction, while restoring the normal control function of the system, providing strong support for the stable operation of the power grid.

[0102] The embodiment takes the example of Southwest Power Grid transmitting electric energy to East China Power Grid through several DC transmission lines to realize the interconnection of the two power grid regions. In order to analyze the coordinated configuration method of DC frequency control and emergency power control, the embodiment takes the example of Binjin DC to conduct instance discussion. In the example setting, the embodiment simulates the emergency action of the safety control system (security control system), requires the Binjin DC power to be urgently reduced by 3000 MW, and assumes that the Binjin DC has already put into the function of the frequency controller, the dead zone of the controller is set to ±0.07 Hz, and the regulation limit is ±800 MW. In order to intuitively show the effect of the coordinated method, the embodiment respectively draws the comparison chart of the Binjin DC power change under the conditions of no action and action of the DC frequency controller (FC) and whether the proposed coordinated method is adopted, as shown in FIGS. Figure 3 、 Figure 4 , Figure 3 、 Figure 4 It can be obviously seen from FIGS. Figure 3 、 Figure 4 that after the proposed coordinated method of the DC frequency controller and the DC emergency power control is adopted, the Binjin DC can accurately adjust its power output according to the requirement of the emergency power control, which fully verifies the effectiveness and practicability of the proposed method.

[0103] The embodiment of the present application provides a high-voltage DC frequency control and emergency power control coordinated configuration method. The method initializes the initial state flag of the high-voltage DC transmission system, obtains the current operating power instruction and the DC system frequency control adjustment amount of the high-voltage DC transmission system according to the current DC operating state of the high-voltage DC transmission system, obtains the DC frequency controller starting value according to the DC system frequency control adjustment amount and the preset DC frequency control action threshold value, calculates the DC emergency power modulation instruction according to the system disturbance monitoring data, and determines the DC emergency power control starting value according to the DC emergency power modulation instruction, starts the DC power coordinated control mechanism according to the DC frequency controller starting value and the DC emergency power control starting value, determines the delay stage frequency controller adjustment amount according to the working state of the DC power coordinated control mechanism, updates the current operating power instruction according to the delay stage frequency controller adjustment amount and the DC emergency power modulation instruction, calculates the DC system operating power update instruction, controls the high-voltage DC transmission system to operate according to the DC system operating power update instruction, and completes the DC active power modulation. Compared with the prior art, the method flexibly adjusts the DC power output according to the real-time state of the high-voltage DC transmission system, realizes the dynamic coordinated control of the power and frequency of the high-voltage DC transmission system, ensures that the system can quickly recover to a stable state when facing a disturbance, and effectively improves the system stability and operating efficiency.

[0104] It should be noted that the size of the serial number of the above processes does not mean the order of execution, the execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0105] In one embodiment, as shown in Figure 5 The system comprises:

[0106] The initial state flag initialization module 101 is configured to initialize initial state flag bits of the HVDC power transmission system, wherein the initial state flag bits comprise a DC emergency power control start initial value and a DC frequency controller start initial value.

[0107] The running frequency analysis module 102 is configured to obtain a current running power instruction and a DC system frequency control adjustment amount of the HVDC power transmission system according to a current DC running state of the HVDC power transmission system.

[0108] The frequency start analysis module 103 is configured to obtain a DC frequency controller start value according to the DC system frequency control adjustment amount and a preset DC frequency control action threshold value.

[0109] The emergency power control module 104 is configured to calculate a DC emergency power modulation instruction according to system disturbance monitoring data, and determine a DC emergency power control start value according to the DC emergency power modulation instruction.

[0110] The delay adjustment control module 105 is configured to start a DC power coordination control mechanism according to the DC frequency controller start value and the DC emergency power control start value, and determine a delay stage frequency controller adjustment amount according to a working state of the DC power coordination control mechanism.

[0111] The running power update module 106 is configured to update the current running power instruction according to the delay stage frequency controller adjustment amount and the DC emergency power modulation instruction, and calculate a DC system running power update instruction.

[0112] The power coordination control module 107 is configured to control the HVDC power transmission system to run according to the DC system running power update instruction, and complete DC active power modulation.

[0113] The specific limitation of the system for coordinating configuration of high-voltage direct-current frequency control and emergency power control can refer to the limitation of the method for coordinating configuration of high-voltage direct-current frequency control and emergency power control, which will not be repeated here. Those skilled in the art can realize that the various modules and steps described in combination with the embodiments disclosed in the present application can be realized in hardware, software or combination of both. Whether the functions are realized in hardware or software depends on the specific application and design constraints of the technical solution. The skilled person can use different methods to realize the described functions for each specific application, but such implementation should not be considered beyond the scope of the present application.

[0114] The embodiment of the present application provides a system for coordinating configuration of high-voltage direct-current frequency control and emergency power control. The system initializes the initial state flag bit of the high-voltage direct-current power transmission system through a flag initialization module. A running frequency analysis module obtains the current running power instruction and the direct-current system frequency control adjustment amount of the high-voltage direct-current power transmission system according to the current direct-current running state of the high-voltage direct-current power transmission system. A frequency start analysis module obtains the direct-current frequency controller start value according to the direct-current system frequency control adjustment amount and the preset direct-current frequency control action threshold value. An emergency power control module calculates the direct-current emergency power modulation instruction according to the system disturbance monitoring data, and determines the direct-current emergency power control start value according to the direct-current emergency power modulation instruction. A delay adjustment control module starts the direct-current power coordination control mechanism according to the direct-current frequency controller start value and the direct-current emergency power control start value, and determines the delay stage frequency controller adjustment amount according to the working state of the direct-current power coordination control mechanism. A running power update module updates the current running power instruction according to the delay stage frequency controller adjustment amount and the direct-current emergency power modulation instruction, and calculates the direct-current system running power update instruction. A power coordination control module controls the high-voltage direct-current power transmission system to run according to the direct-current system running power update instruction, and completes the direct-current active power modulation. Compared with the prior art, the system flexibly adjusts the direct-current power output according to the real-time state of the high-voltage direct-current power transmission system, realizes the dynamic coordination control of the power and frequency of the high-voltage direct-current power transmission system, ensures that the system can quickly recover to a stable state when facing a disturbance, and effectively improves the system stability and running efficiency.

[0115] The above-described embodiments only express several preferred embodiments of the present application, and the description is relatively specific and detailed, but it should not be understood as limiting the scope of the patent. It should be noted that for ordinary skilled persons in the technical field, several improvements and replacements can be made without departing from the technical principles of the present application, and these improvements and replacements should be considered as the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the protection scope of the claims.

Claims

1. A method for coordinating high-voltage DC frequency control and emergency power control, characterized in that, The method comprises the following steps: initializing an initial state flag of the HVDC power transmission system; the initial state flag comprises an initial value of DC emergency power control start and an initial value of DC frequency controller start; obtaining a current operating power instruction and a DC system frequency control adjustment amount of the HVDC power transmission system according to a current DC operating state of the HVDC power transmission system; obtaining a DC frequency controller start value according to the DC system frequency control adjustment amount and a preset DC frequency control action threshold value; obtaining a DC emergency power modulation instruction according to system disturbance monitoring data, and determining a DC emergency power control start value according to the DC emergency power modulation instruction; starting a DC power coordination control mechanism according to the DC frequency controller start value and the DC emergency power control start value, and determining a delay stage frequency controller adjustment amount according to a working state of the DC power coordination control mechanism; updating the current operating power instruction according to the delay stage frequency controller adjustment amount and the DC emergency power modulation instruction, and calculating a DC system operating power update instruction; controlling the HVDC power transmission system to operate according to the DC system operating power update instruction, and completing DC active power modulation.

2. The method of claim 1, wherein the HVDC frequency control and emergency power control coordination configuration method is characterized by, The step of obtaining the current operating power instruction and the DC system frequency control adjustment amount according to the current DC operating state of the HVDC power transmission system comprises: collecting DC voltage data and DC current data of the HVDC power transmission system, and calculating a current DC power according to the DC voltage data and the DC current data; determining the current operating power instruction of the HVDC power transmission system according to power system dispatching requirements, the current DC power and a rated power of the HVDC power transmission system; collecting AC system frequency measurement data, and comparing the AC system frequency measurement data with a preset frequency reference value to calculate a frequency deviation; calculating the frequency control adjustment amount by using a proportional-integral controller according to the frequency deviation.

3. The method of claim 1, wherein the HVDC frequency control and emergency power control coordination configuration method is characterized by, The step of obtaining the DC frequency controller start value according to the DC system frequency control adjustment amount and the preset DC frequency control action threshold value comprises: comparing the DC system frequency control adjustment amount with the DC frequency control action threshold value, if the DC system frequency control adjustment amount exceeds the DC frequency control action threshold value, determining that the DC frequency controller starts earlier than the emergency power control, and setting the DC frequency controller start value as one; if the DC system frequency control adjustment amount does not exceed the DC frequency control action threshold value, determining that the emergency power control starts earlier than the DC frequency controller, and setting the DC frequency controller start value as zero.

4. The method of claim 1, wherein the HVDC frequency control and emergency power control coordination configuration method is characterized by, The step of determining the DC emergency power control start value according to the DC emergency power modulation instruction comprises: comparing an absolute value of the DC emergency power modulation instruction with a preset emergency power control action threshold value, if the absolute value of the DC emergency power modulation instruction is greater than the emergency power control action threshold value, determining to start the emergency power control, and setting the DC emergency power control start value as one; If the absolute value of the DC emergency power modulation instruction is equal to the emergency power control action threshold, it is determined that the emergency power control is blocked, the DC emergency power control start value is set to zero.

5. The method of claim 1, wherein the HVDC frequency control and emergency power control coordination configuration method is characterized by, The step of starting the DC power coordination control mechanism according to the sum of the DC frequency controller start value and the DC emergency power control start value comprises: The sum of the DC frequency controller start value and the DC emergency power control start value is obtained to obtain a start timing flag and; The start timing flag and is multiplied by the DC emergency power control start value to obtain a DC power coordination control flag value, and the DC power coordination control mechanism is started according to the DC power coordination control flag value.

6. The method of claim 1, wherein the HVDC frequency control and emergency power control coordination configuration method is characterized by, The step of determining the delay stage frequency controller adjustment amount according to the working state of the DC power coordination control mechanism comprises: When the DC power coordination control mechanism is started, the DC frequency controller start value is assigned to the delay stage frequency controller adjustment amount; When the DC power coordination control mechanism is not started, the delay stage frequency controller adjustment amount is set to zero.

7. The method of claim 1, wherein the HVDC frequency control and emergency power control coordination configuration method is characterized by, The step of updating the current operating power instruction according to the delay stage frequency controller adjustment amount and the DC emergency power modulation instruction to obtain a DC system operating power update instruction comprises: The current operating power instruction is added to the delay stage frequency controller adjustment amount and the DC emergency power modulation instruction to obtain the DC system operating power update instruction.

8. The method of claim 1, wherein the HVDC frequency control and emergency power control coordination configuration is characterized by, After the control HVDC power transmission system is operated according to the DC system operating power update instruction to complete the DC active power modulation step, the method further comprises: The delay time is determined according to the working state of the DC power coordination control mechanism, and after the delay time ends, the DC frequency controller blocking state is released, the DC frequency controller and the emergency power control function are restored, and the HVDC power transmission system is restored to a normal operating state.

9. The method of claim 8, wherein the HVDC frequency control and emergency power control coordination configuration is characterized by: The delay time is determined according to the DC frequency controller blocking duration of different DC power coordination control mechanisms.

10. A high voltage direct current frequency control and emergency power control coordination configuration system, characterized in that, The system comprises: A flag initialization module is configured to initialize initial state flag bits of the HVDC power transmission system; the initial state flag bits comprise a DC emergency power control start initial value and a DC frequency controller start initial value; An operating frequency analysis module is configured to obtain a current operating power instruction and a DC system frequency control adjustment amount of the HVDC power transmission system according to a current DC operating state of the HVDC power transmission system; A frequency start analysis module is configured to obtain a DC frequency controller start value according to the DC system frequency control adjustment amount and a preset DC frequency control action threshold; An emergency power control module is configured to obtain a DC emergency power modulation instruction according to system disturbance monitoring data, and determine a DC emergency power control start value according to the DC emergency power modulation instruction; The time-delay adjustment control module is configured to start a DC power coordination control mechanism according to the DC frequency controller starting value and the DC emergency power control starting value, and determine a time-delay stage frequency controller adjustment amount according to a working state of the DC power coordination control mechanism. The operation power updating module is configured to update the current operation power instruction according to the time-delay stage frequency controller adjustment amount and the DC emergency power modulation instruction, and calculate a DC system operation power updating instruction. The power coordination control module is configured to control the HVDC power transmission system to operate according to the DC system operation power updating instruction, and complete the DC active power modulation.

Images