Adaptive three-phase reclosing method, system, equipment, medium and product of new energy station sending-out line

Abstract

The invention relates to the technical field of new energy stations, in particular to a new energy station sending-out line adaptive three-phase reclosing method, system, device, medium and product, according to the method, under the condition that a sending-out line of a new energy station breaks down, stable island operation of the new energy station is maintained based on energy storage networking control, and the new energy station sending-out line adaptive three-phase reclosing method is achieved. The fault property is judged by actively injecting a voltage signal into a fault sending-out line, under the condition of an instantaneous fault, a system side circuit breaker is reclosed, voltage signal parameters on the two sides of a field station side circuit breaker are pre-synchronized, the voltage amplitude difference and the phase difference are eliminated, smooth re-grid connection of a new energy field station is ensured, and after pre-synchronization is completed, the system side circuit breaker and the field station side circuit breaker are connected in parallel. The reclosing operation is carried out by controlling the field station side circuit breaker, re-grid connection of the new energy field station is realized, the reliability of reclosing is improved, and normal operation of the new energy field station is guaranteed.

Description

Technical Field

[0001] The present invention relates to the technical field of new energy stations, and in particular to a method, system, equipment, medium and product for adaptive three-phase reclosing of a transmission line of a new energy station. Background Art

[0002] With the development of new power systems and the large-scale access of new energy, it is a major development trend to collect new energy through AC power grids and then send it out through flexible DC lines. Most new energy stations are located in remote areas, and AC transmission lines are often affected by severe weather and complex environments, resulting in an increased probability of failure, which poses a great threat to the safe and stable operation of new power systems that lack inertial support.

[0003] Given that transient faults account for more than 80% of power transmission line faults in power systems, automatic reclosing technology has become a key means to improve the reliability of system power supply by quickly restoring power supply after a transient power outage, and is now widely used in power grids. However, the inertia of the new energy sending-end system is low and the anti-disturbance ability is weak. The traditional automatic reclosing technology lacks a precise fault nature identification mechanism and is prone to mistakenly close to a permanent fault. This will trigger a secondary impact, aggravate equipment stress damage, and even induce a chain disconnection of new energy units, seriously threatening the transient stable operation of the power grid. New energy stations equipped with grid-type energy storage have certain voltage construction and control capabilities. How to make full use of this capability of grid-type energy storage to realize the fault nature identification and adaptive reclosing of the transmission line to avoid mistaken closing to a permanent fault is a technical problem that needs to be solved urgently.

[0004] At present, new energy stations widely use transmission lines without parallel reactors. The electrical characteristics become blurred after the fault arc is extinguished, and the transient process is highly random, making it difficult to reliably identify the fault, resulting in low reliability of reclosing, which affects the normal operation of new energy stations. Summary of the invention

[0005] In view of this, the present invention provides a method, system, equipment, medium and product for adaptive three-phase reclosing of a new energy station transmission line, which solves the technical problem that new energy stations widely use transmission lines without parallel reactors, the electrical characteristics are blurred after the fault arc is extinguished, the transient process is highly random, and it is difficult to reliably identify the fault, resulting in low reliability of reclosing and affecting the normal operation of the new energy station.

[0006] A first aspect of the present invention provides a method for adaptively reclosing a three-phase circuit breaker of a new energy station transmission line, the method comprising:

[0007] In the event of a failure in the transmission line of the new energy station, controlling the new energy station to enter an island operation mode;

[0008] By actively injecting a voltage signal into the faulty transmission line, it is determined whether the faulty transmission line is a transient fault;

[0009] When it is determined that the faulty transmission line is the instantaneous fault, reclosing the circuit breaker on the system side;

[0010] The voltage signal parameters on both sides of the station-side circuit breaker are pre-synchronized through the energy storage pre-synchronization control logic;

[0011] After the pre-synchronization is completed, the circuit breaker on the station side is reclosed to switch the new energy station from the island operation mode to the operation mode connected to the transmission line.

[0012] Preferably, the method further comprises:

[0013] In the event of a fault in the transmission line of a new energy station, the new energy station is controlled to enter the low voltage ride-through operation mode, and then the circuit breakers on both sides of the faulty transmission line are tripped.

[0014] Preferably, controlling the new energy station to enter the island operation mode comprises: controlling the new energy station to enter the island operation mode by using the energy storage power station through a droop control method;

[0015] The method of controlling the new energy station to enter the island operation mode by using the energy storage power station through a droop control method includes:

[0016] Obtaining active power measurement values ​​and three-phase voltage measurement values ​​of the energy storage power station;

[0017] Comparing the difference between the active power measurement value and the active power reference value to obtain an active power difference;

[0018] The active power difference is adjusted by using a preset droop coefficient to obtain an angular frequency;

[0019] The angular frequency is transformed by a preset system angular frequency to obtain a reference frequency, and an integration operation is performed on the reference frequency to obtain a reference phase;

[0020] Using the reference phase, the voltage d-axis component and the voltage q-axis component are obtained by coordinate transformation of the three-phase voltage measurement values;

[0021] Comparing the voltage d-axis component and the voltage q-axis component with the reference value of the voltage d-axis component and the reference value of the voltage q-axis component respectively, and inputting the difference into a proportional-integral controller to obtain a current d-axis reference component and a current q-axis reference component;

[0022] Inputting the current d-axis reference component and the current q-axis reference component into a current control link to obtain a valve-side voltage d-axis reference component and a valve-side voltage q-axis reference component;

[0023] By using the reference phase, the valve side voltage d-axis reference component and the valve side voltage q-axis reference component are subjected to coordinate transformation and modulation to obtain a trigger pulse signal of an inverter circuit of an energy storage power station;

[0024] The amplitude and phase of the three-phase voltage of the new energy station are adjusted by the trigger pulse signal.

[0025] Preferably, the step of actively injecting a voltage signal into the faulty transmission line to determine whether the faulty transmission line is a transient fault comprises:

[0026] Actively inject a voltage signal into the faulty transmission line by using the energy storage power station in the new energy station, and monitor the effective value of each phase voltage of the faulty transmission line after the voltage signal is injected;

[0027] Comparing the effective value of each phase voltage with a preset voltage threshold;

[0028] When it is determined that the effective values ​​of the voltages of each phase are greater than the preset voltage threshold, it is determined that the faulty transmission line is the instantaneous fault;

[0029] When it is determined that the effective values ​​of the voltages of each phase are not all greater than the preset voltage threshold, it is determined that the faulty transmission line is a permanent fault.

[0030] Preferably, the pre-synchronization of voltage signal parameters on both sides of the station-side circuit breaker by energy storage pre-synchronization control logic includes:

[0031] Acquire a first voltage amplitude and a second voltage amplitude respectively corresponding to two sides of the station-side circuit breaker, and acquire a first voltage phase and a second voltage phase respectively corresponding to two sides of the station-side circuit breaker;

[0032] Inputting the first voltage amplitude and the second voltage amplitude into a proportional-integral controller to obtain a voltage amplitude deviation value, and inputting the first voltage phase and the second voltage phase into the proportional-integral controller to obtain a voltage phase deviation value;

[0033] The deviation value of the voltage amplitude and the deviation value of the voltage phase are respectively superimposed on the voltage d-axis component reference value in the energy storage voltage loop control and the reference phase of the energy storage network control, so that the voltage signal parameters on both sides of the station-side circuit breaker are synchronized.

[0034] Preferably, the method further comprises:

[0035] After the new energy station is connected to the transmission line, the new energy station maintains an active power reduction output operation mode for a preset period of time and then restores the active power output before the fault.

[0036] In a second aspect, the present invention provides an adaptive three-phase reclosing system for a new energy station transmission line, the system comprising:

[0037] A network control module, used to control the new energy station to enter an island operation mode when a transmission line of the new energy station fails, and actively inject a voltage signal into the faulty transmission line;

[0038] A fault nature determination module, used to determine whether the faulty output line is a transient fault after actively injecting a voltage signal into the faulty output line;

[0039] A first circuit breaker control module, configured to reclose the circuit breaker on the system side when it is determined that the faulty transmission line is the instantaneous fault;

[0040] The voltage synchronization module is used to pre-synchronize the voltage signal parameters on both sides of the circuit breaker on the station side through the energy storage pre-synchronization control logic;

[0041] The second circuit breaker control module is used to reclose the circuit breaker on the station side after completing the pre-synchronization, so that the new energy station switches from the island operation mode to the operation mode connected to the transmission line.

[0042] In a third aspect, the present invention provides an electronic device, comprising a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor executes the steps of the adaptive three-phase reclosing method for the new energy station transmission line as described in the first aspect.

[0043] In a fourth aspect, the present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed, implements the steps of the method for adaptive three-phase reclosing of a new energy station transmission line as described in the first aspect.

[0044] In a fifth aspect, the present invention provides a computer program product, comprising a computer program stored on a non-transitory computer-readable storage medium, wherein the computer program comprises program instructions, wherein when the program instructions are executed by a computer, the computer executes the steps of the method for adaptive three-phase reclosing of a new energy station transmission line as described in the first aspect.

[0045] It can be seen from the above technical solutions that the present invention maintains the stable operation of the new energy station island based on the energy storage network control when a fault occurs in the transmission line of the new energy station, and judges the nature of the fault by actively injecting a voltage signal into the faulty transmission line, and in the case of a transient fault, recloses the system side circuit breaker, and pre-synchronizes the voltage signal parameters on both sides of the station side circuit breaker to eliminate the voltage amplitude difference and phase difference, ensuring smooth re-grid connection of the new energy station, and after completing the pre-synchronization, controls the station side circuit breaker to perform the reclosing operation to achieve re-grid connection of the new energy station, improve the reliability of the reclosing, and ensure the normal operation of the new energy station. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0047] Figure 1 An application environment of an adaptive three-phase reclosing method for a new energy station transmission line provided by an embodiment of the present invention;

[0048] Figure 2 A flow chart of an adaptive three-phase reclosing method for a new energy station transmission line provided by an embodiment of the present invention;

[0049] Figure 3 A schematic diagram of the topological structure of a new energy station and its AC transmission line provided in an embodiment of the present invention;

[0050] Figure 4 A flowchart of the operation of the adaptive three-phase reclosing method for the transmission line of a new energy station provided in an embodiment of the present invention;

[0051] Figure 5 A control block diagram of droop control provided by an embodiment of the present invention;

[0052] Figure 6 A block diagram of a voltage loop control provided by an embodiment of the present invention;

[0053] Figure 7 A control block diagram of a voltage / phase pre-synchronization control mode provided by an embodiment of the present invention;

[0054] Figure 8 A schematic diagram of the structure of an adaptive three-phase reclosing system for a new energy station transmission line provided by an embodiment of the present invention;

[0055] Fig. 9A schematic diagram of the structure of an electronic device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0056] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0057] The adaptive three-phase reclosing method for the transmission line of the new energy station provided in the embodiment of the present application can be applied to Figure 1 In the application environment shown. Among them, the terminal 101 communicates with the server 102 through the network. The data storage system can store the data that the server 102 needs to process. The data storage system can be integrated on the server 102, or it can be placed on the cloud or other network servers. When a fault occurs in the transmission line of the new energy station, the terminal 101 or the server 102 controls the new energy station to enter the island operation mode; by actively injecting a voltage signal into the faulty transmission line, it is determined whether the faulty transmission line is a transient fault; when it is determined that the faulty transmission line is a transient fault, the system side circuit breaker is reclosed; through the energy storage pre-synchronization control logic, the voltage signal parameters on both sides of the station side circuit breaker are pre-synchronized; after the pre-synchronization is completed, the station side circuit breaker is reclosed to switch the new energy station from the island operation mode to the grid-connected transmission line operation mode.

[0058] The terminal 101 may be, but is not limited to, various personal computers, laptop computers, smart phones, tablet computers, and the like.

[0059] The server 102 may be an independent physical server, or a server cluster or distributed system composed of multiple physical servers, or a cloud server that provides cloud computing services.

[0060] like Figure 2 As shown, a method for adaptive three-phase reclosing of a new energy station transmission line is provided. Figure 1 The terminal 101 or the server 102 in the example is used to illustrate, and the steps include the following steps S1 to S5. Among them:

[0061] Step S1: When a failure occurs in the transmission line of the new energy station, the new energy station is controlled to enter an island operation mode.

[0062] Among them, the transmission line of the new energy station refers to the line that the new energy station uses to transmit electricity to the power grid. When a transmission line fails, in order to ensure the safety of the new energy station and rapid recovery after the failure, the system first controls the new energy station to enter the island operation mode. The island operation mode refers to the state where the new energy station is disconnected from the power grid and operates independently. At this time, the new energy station needs to rely on its own energy storage or control strategy to maintain stable operation.

[0063] Step S2: actively injecting a voltage signal into the faulty output line to determine whether the faulty output line is a transient fault.

[0064] Among them, active voltage signal injection is to use the power supply or energy storage equipment of the new energy station to apply a known voltage signal to the fault line. By monitoring the response of the voltage signal on the fault line, the characteristics of the fault line can be analyzed to determine whether the fault is a transient fault.

[0065] Exemplarily, the circuit breaker at the station side is briefly reclosed, and a voltage signal is actively injected into the faulty outgoing line through an energy storage device.

[0066] Transient faults usually refer to those that disappear on their own in a short time, such as a short short circuit caused by a line contacting a tree branch. Permanent faults refer to those that require repair or replacement of equipment to eliminate, such as a broken line or damaged equipment.

[0067] By actively injecting voltage signals and monitoring their responses, the two fault types can be accurately distinguished, providing a reliable basis for subsequent reclosing operations.

[0068] Step S3: When it is determined that the faulty transmission line is a transient fault, a reclosing operation is performed on the circuit breaker on the system side.

[0069] The system-side circuit breaker refers to the circuit breaker that connects the transmission line to the power grid. After confirming that the fault is a transient fault, the system controls the circuit breaker to perform a reclosing operation to restore the connection between the transmission line and the power grid.

[0070] Step S4: Pre-synchronize the voltage signal parameters on both sides of the station-side circuit breaker through the energy storage pre-synchronization control logic.

[0071] Among them, the energy storage pre-synchronization control logic is to ensure that at the moment of reclosing, the voltage signal parameters on both sides of the circuit breaker on the station side match, thereby avoiding the impact current and voltage fluctuations that may be generated during the reclosing process, and protecting the safe operation of equipment and systems.

[0072] The station-side circuit breaker refers to the circuit breaker that connects the renewable energy station to the transmission line. After completing the reclosing operation of the system-side circuit breaker, in order to ensure that the renewable energy station can be smoothly and stably reconnected to the grid, it is necessary to pre-synchronize the voltage signal parameters (such as voltage amplitude and phase) on both sides of the station-side circuit breaker.

[0073] Step S5: After completing the pre-synchronization, reclosing operation is performed on the circuit breaker at the station side, so that the new energy station is switched from the island operation mode to the grid-connected operation mode of the transmission line.

[0074] Among them, after completing the above-mentioned pre-synchronization operation, the new energy station is reconnected with the transmission line by reclosing the station-side circuit breaker, and a smooth transition is made from the island operation mode to the grid-connected operation mode.

[0075] It should be noted that the embodiment of the present application maintains the stable operation of the new energy station island based on the energy storage network control when a fault occurs in the transmission line of the new energy station, and judges the nature of the fault by actively injecting a voltage signal into the faulty transmission line. In the case of a transient fault, the system side circuit breaker is reclosed, and the voltage signal parameters on both sides of the station side circuit breaker are pre-synchronized to eliminate the voltage amplitude difference and the phase difference, ensuring smooth re-grid connection of the new energy station. After completing the pre-synchronization, the re-closing operation is performed by controlling the station side circuit breaker to achieve re-grid connection of the new energy station, thereby improving the reliability of the reclosing operation and ensuring the normal operation of the new energy station.

[0076] In some embodiments, the method further comprises:

[0077] In the event of a fault in the transmission line of a new energy station, the new energy station is controlled to enter the low voltage ride-through operation mode, and then the circuit breakers on both sides of the faulty transmission line are tripped.

[0078] Among them, the low voltage ride-through operation mode means that when the voltage at the grid connection point of the new energy station drops, the new energy station can maintain grid connection operation for a period of time, and even provide a certain amount of reactive power support to the grid until the grid disturbance is cleared or the new energy station's own protection action trips. This operation mode helps to reduce the risk of new energy stations being disconnected from the grid during grid disturbances and improve the stability and reliability of the grid. After controlling the new energy station to enter the low voltage ride-through operation mode, the system can monitor the recovery of the grid connection point voltage. Before the protection action trips, once the grid connection point voltage returns to normal, the new energy station can be controlled to exit the low voltage ride-through operation mode and resume normal power generation and power supply functions.

[0079] For example, a fault occurs in the AC transmission line of a new energy station, the voltage at the grid connection point drops, the photovoltaic station enters low voltage ride-through, and keeps the active power reduced by limiting the active current reference value before reconnecting to the grid. The energy storage power station enters low voltage ride-through and starts the charging mode, and then the protection action trips the three-phase circuit breakers on both sides of the transmission line.

[0080] In some embodiments, controlling the new energy station to enter the island operation mode includes: using the energy storage power station to control the new energy station to enter the island operation mode through a droop control method.

[0081] Among them, the droop control method refers to adjusting the voltage phase and amplitude output by energy storage or other devices so that the new energy station can maintain a stable island operation state when the external grid support is lost. The droop control strategy simulates the droop characteristics of traditional synchronous generators, allowing the new energy station to automatically distribute power in the island mode to maintain system stability.

[0082] Specifically, the energy storage power station is used to control the new energy station to enter the island operation mode through the droop control method, including:

[0083] Step S101, obtaining the active power measurement value and the three-phase voltage measurement value of the energy storage power station;

[0084] Step S102: performing a difference comparison between the active power measurement value and the active power reference value to obtain an active power difference;

[0085] Step S103, adjusting the active power difference using a preset droop coefficient to obtain an angular frequency;

[0086] Step S104, transforming the angular frequency by a preset system angular frequency to obtain a reference frequency, and integrating the reference frequency to obtain a reference phase;

[0087] Step S105, using the reference phase, transforming the three-phase voltage measurement values ​​to obtain the voltage d-axis component and the voltage q-axis component;

[0088] Step S106, performing difference comparison between the voltage d-axis component and the voltage q-axis component and the reference value of the voltage d-axis component and the reference value of the voltage q-axis component respectively, and inputting the difference into a proportional-integral controller to obtain a current d-axis reference component and a current q-axis reference component;

[0089] Step S107, inputting the current d-axis reference component and the current q-axis reference component into the current control link to obtain the valve-side voltage d-axis reference component and the valve-side voltage q-axis reference component;

[0090] Among them, the current control loop is usually used as the inner loop of the droop control, working in conjunction with the voltage control outer loop to control the inverter output current based on the current reference value output by the voltage loop. The output of the current control link is usually the inverter valve side voltage reference value in the dq rotating coordinate system. After the valve side voltage reference value is transformed into the dq / abc coordinate system, it becomes the reference modulation wave of the modulation link.

[0091] Step S108, using the reference phase, the valve side voltage d-axis reference component and the valve side voltage q-axis reference component are subjected to coordinate transformation and modulation to obtain a trigger pulse signal of the inverter circuit of the energy storage power station;

[0092] Among them, the modulation link: compares the reference modulation wave with the high-frequency carrier signal to generate a trigger pulse signal for controlling the opening and closing of the inverter bridge arm.

[0093] Step S109: adjusting the amplitude and phase of the three-phase voltage of the new energy station by triggering a pulse signal.

[0094] In some embodiments, actively injecting a voltage signal into the faulty transmission line to determine whether the faulty transmission line is a transient fault includes:

[0095] Step S201: using the energy storage power station in the new energy station to actively inject a voltage signal into the faulty transmission line, and monitoring the effective value of each phase voltage of the faulty transmission line after the voltage signal is injected;

[0096] Step S202, comparing the effective value of each phase voltage with a preset voltage threshold;

[0097] Step S203: when it is determined that the effective values ​​of the voltages of each phase are greater than the preset voltage threshold, it is determined that the faulty transmission line is a transient fault;

[0098] Step S204: When it is determined that the effective values ​​of the voltages of each phase are not all greater than the preset voltage threshold, it is determined that the faulty transmission line is a permanent fault.

[0099] Exemplarily, the voltage of the transmission line is relatively stable for a period of time during the phase in which the energy storage power station in the new energy station actively injects a voltage signal into the faulty transmission line, and the effective value of the A-phase voltage, B-phase voltage and C-phase voltage of the transmission line in this period of time is determined. If the effective value is greater than 0.8pu, the corresponding determination result is marked as 1; otherwise, the corresponding determination result is marked as 0. If the three determination results are all 1, it indicates that the three-phase voltage of the transmission line can be established, and the previous fault is a transient fault and has been eliminated at this time; otherwise, it indicates that the previous fault is a permanent fault, and the new energy station needs to be locked and the transmission line needs to be repaired.

[0100] In some embodiments, the voltage signal parameters on both sides of the station-side circuit breaker are pre-synchronized through energy storage pre-synchronization control logic, including:

[0101] Step S401, obtaining a first voltage amplitude and a second voltage amplitude respectively corresponding to two sides of a station-side circuit breaker, and obtaining a first voltage phase and a second voltage phase respectively corresponding to two sides of a station-side circuit breaker;

[0102] Step S402, inputting the first voltage amplitude and the second voltage amplitude into a proportional-integral controller to obtain a deviation value of the voltage amplitude, and inputting the first voltage phase and the second voltage phase into the proportional-integral controller to obtain a deviation value of the voltage phase;

[0103] Step S403: superimpose the voltage amplitude deviation value and the voltage phase deviation value on the voltage d-axis component reference value in the energy storage voltage loop control and the reference phase of the energy storage network control, so as to synchronize the voltage signal parameters on both sides of the station-side circuit breaker.

[0104] Among them, by superimposing the detected voltage amplitude deviation value and voltage phase deviation value on the voltage d-axis component reference value in the energy storage voltage loop control and the reference phase of the energy storage network control respectively, the voltage signal parameters on both sides of the station-side circuit breaker can be accurately synchronized to ensure the stable operation of the entire power system.

[0105] In some embodiments, the method further comprises:

[0106] After the new energy station is connected to the transmission line, the new energy station maintains the active power output reduced for a preset period of time in the operation mode and then restores the active power output before the fault.

[0107] It is understandable that after the photovoltaic station continues to maintain a reduced active output for a period of time, the photovoltaic station restores the active output before the fault. At this time, the new energy station re-enters the normal power generation and power supply state, ensuring the safe and stable operation of the new energy station while reducing the impact on the power grid. In this way, the adaptive three-phase reclosing method for the transmission line of the new energy station provided by the embodiment of the present invention not only improves the reliability of the reclosing, but also effectively ensures the normal operation of the new energy station and reduces the impact and influence of the fault on the power grid.

[0108] In an exemplary embodiment, in order to more clearly illustrate the specific steps of a method for adaptive three-phase reclosing of a new energy station transmission line provided in an embodiment of the present application, the method for adaptive three-phase reclosing of a new energy station transmission line is specifically described below using a specific example.

[0109] In this example, the scenario is the AC transmission line of the new energy station. The topological structure of the new energy station and its AC transmission line is as follows: Figure 3 As shown in the figure, its electrical part consists of photovoltaic station, energy storage station, low-voltage AC bus, transformer, high-voltage AC bus, voltage transformer (PT), circuit breaker, etc. The photovoltaic station consists of a large number of photovoltaic strings that are first boosted by the DC / DC boost circuit, then inverted into AC power by the DC / AC inverter circuit, and then collected to the low-voltage AC bus. The energy storage station is composed of energy storage batteries that are inverted, boosted, and collected. The photovoltaic station adopts the grid-following control mode. In the steady-state mode, its DC / DC boost circuit mainly realizes the maximum power point tracking (MPPT) control of the photovoltaic string, and its DC / AC inverter circuit mainly controls the DC side voltage stability; after entering the low-voltage ride-through mode, its DC / DC boost circuit mainly controls the DC voltage stability, and its DC / AC inverter circuit is mainly used to realize the AC side current control. These are common control modes and will not be repeated.

[0110] The energy storage power station adopts a grid-building control mode. The grid-building control strategy adopted by the energy storage power station is droop control, on this basis, voltage / phase pre-synchronization control is added in the island-grid conversion stage.

[0111] Specifically, the operation flow chart of the adaptive three-phase reclosing method for the new energy station transmission line in this example is as follows: Figure 4 As shown, the specific steps are as follows:

[0112] (1) When the AC transmission line of the new energy station fails, the photovoltaic station enters low voltage ride through and limits the active current reference value I before reconnecting to the grid. PVdref Keep the active power reduced, the energy storage power station enters low voltage ride-through, starts charging mode, and then the protection action trips the three-phase circuit breakers on both sides of the transmission line. The energy storage builds voltage / frequency support through droop control, allowing the entire new energy station to enter island operation mode.

[0113] Among them, the control block diagram of droop control is as follows Figure 5 As shown, where P Eref is the active power reference value, P E is the measured value of active power, K droop is the droop coefficient, 1 / s is the integral link, ω N is the system angular frequency, f gfm The reference frequency generated for droop control, θ gfm The reference phase generated for droop control. Phase θ gfm For energy storage battery three-phase voltage u Eabc abc / dq coordinate transformation (abc three-phase coordinate system is transformed into dq rotating coordinate system).

[0114] Among them, the voltage loop control block diagram is as follows Figure 6 As shown, where u Ed and u EqThey are the three-phase voltages u of the energy storage battery Eabc The reference values ​​of the d-axis component and the q-axis component obtained after the abc / dq coordinate transformation are u Edref and 0, PI is a proportional-integral controller. The outputs of the two proportional-integral controllers are the voltage loop output and the current loop reference value, which are I Edref and I Eqref The current loop output is the reference value of the valve side d-axis voltage and q-axis voltage. After the valve side voltage reference value is transformed and modulated by dq / abc, it becomes the trigger pulse signal of the energy storage battery DC / AC inverter circuit. This part is a common control mode and will not be described in detail.

[0115] (2) After the fault occurs t1 time later, the second circuit breaker on the station side is reclosed, and the voltage constructed by the energy storage power station is used to actively inject the fault nature of the faulty transmission line.

[0116] ① If it is judged to be a permanent fault, the second circuit breaker will be tripped again to lock the PV station and wait for line maintenance.

[0117] ② If it is determined to be a transient fault, the second circuit breaker is tripped to prepare for subsequent voltage / phase pre-synchronization control and grid connection again;

[0118] Among them, referring to Table 1, the method and criteria for judging the nature of the fault of the transmission line of the new energy station based on the active injection of the grid-building energy storage are as follows:

[0119] After a fault occurs in the transmission line, the protection action trips the three-phase circuit breakers on both sides of the line. The energy storage power station builds voltage / frequency support through droop control, allowing the entire new energy station to enter island operation mode. After the island operation is stable, the second circuit breaker (three-phase circuit breaker) on the station side is closed, and the voltage built by the energy storage is used to actively determine the nature of the fault on the transmission line. The nature of the fault is determined by whether the voltage of the transmission line can be established to determine whether it is a transient fault or a permanent fault.

[0120] Specifically, a period of time during the active injection phase when the voltage of the transmission line is relatively stable is examined, and the effective values ​​of the A-phase voltage, the B-phase voltage, and the C-phase voltage in the period are calculated respectively. If the effective value is greater than 0.8pu, the corresponding judgment result is marked as 1; otherwise, the corresponding judgment result is marked as 0. If the three judgment results are all 1, it indicates that the three-phase voltage of the transmission line can be established, and the previous fault is a transient fault and has been eliminated at this time; otherwise, it indicates that the previous fault is a permanent fault.

[0121] Table 1

[0122]

[0123] (3) After t2, the first circuit breaker on the system side is closed; after t3, the energy storage enters the voltage / phase pre-synchronization control mode; after t4, the second circuit breaker on the station side is closed, the energy storage exits the voltage / phase pre-synchronization control mode and ends the charging mode. At this point, the new energy station is connected to the grid again;

[0124] Among them, the control block diagram of the voltage / phase pre-synchronization control mode is as follows Figure 7 As shown, U 21 , U 22 are the voltage amplitudes on the left and right sides of the second circuit breaker, θ 21 ,θ 22 They are the voltage phases on the left and right sides of the second circuit breaker. 21 and U 22 The deviation value of the voltage amplitude is obtained after the proportional-integral controller is used to obtain the deviation value ΔU, θ 21 and θ 22 The deviation value of the voltage amplitude is obtained after passing through the integral controller.

[0125] When the voltage / phase presynchronization control is turned on, ΔU is superimposed on the voltage d-axis component reference value u in the energy storage voltage loop control. Edref Δθ is superimposed on the reference phase θ generated by the energy storage droop control gfm When voltage / phase synchronization is achieved, the second circuit breaker can be closed for synchronization.

[0126] (4) The PV station continues to maintain a reduced active output for a period of time. After time t5, the PV station restores the active output before the fault. At this point, all adaptive three-phase reclosing operations are completed.

[0127] Based on the same inventive concept, an embodiment of the present application also provides an adaptive three-phase reclosing system for a new energy station transmission line for implementing the adaptive three-phase reclosing method for a new energy station transmission line involved above.

[0128] The implementation solution for solving the problem provided by the system is similar to the implementation solution recorded in the above method. Therefore, the specific limitations in the embodiments of the adaptive three-phase reclosing system for the transmission lines of one or more new energy stations provided below can be referred to the limitations on the adaptive three-phase reclosing method for the transmission lines of new energy stations in the above text, and will not be repeated here.

[0129] like Figure 8 As shown, the embodiment of the present application provides an adaptive three-phase reclosing system for a new energy station transmission line, and the system includes:

[0130] The network control module 100 is used to control the new energy station to enter the island operation mode when a transmission line of the new energy station fails, and actively inject a voltage signal into the faulty transmission line;

[0131] The fault nature determination module 200 is used to determine whether the faulty output line is a transient fault after actively injecting a voltage signal into the faulty output line;

[0132] The first circuit breaker control module 300 is used to reclose the system-side circuit breaker when it is determined that the faulty transmission line is a transient fault;

[0133] The voltage synchronization module 400 is used to pre-synchronize the voltage signal parameters on both sides of the station-side circuit breaker through the energy storage pre-synchronization control logic;

[0134] The second circuit breaker control module 500 is used to reclose the circuit breaker on the station side after completing pre-synchronization, so that the new energy station switches from the island operation mode to the grid-connected operation mode of the transmission line.

[0135] In some embodiments, the system further comprises:

[0136] The low voltage ride through control module is used to control the new energy station to enter the low voltage ride through operation mode when a fault occurs in the transmission line of the new energy station and when the voltage at the grid connection point of the new energy station drops to a preset voltage drop threshold.

[0137] The fault protection module is used to generate instructions to trip the circuit breakers on both sides of the faulty transmission line when a fault occurs in the transmission line of the new energy station.

[0138] In some embodiments, the network control module 100 is used to control the new energy station to enter the island operation mode by using the energy storage power station through the droop control method;

[0139] Among them, the energy storage power station is used to control the new energy station to enter the island operation mode through the droop control method, including:

[0140] Obtain active power measurement values ​​and three-phase voltage measurement values ​​of the energy storage power station;

[0141] Comparing the difference between the active power measurement value and the active power reference value, the active power difference is obtained;

[0142] The active power difference is adjusted using a preset droop coefficient to obtain an angular frequency;

[0143] The angular frequency is transformed by a preset system angular frequency to obtain a reference frequency, and the reference frequency is integrated to obtain a reference phase;

[0144] Using the reference phase, the voltage d-axis component and the voltage q-axis component are obtained by coordinate transformation of the three-phase voltage measurement values;

[0145] The voltage d-axis component and the voltage q-axis component are respectively compared with the reference value of the voltage d-axis component and the reference value of the voltage q-axis component, and the difference is input into the proportional-integral controller to obtain the current d-axis reference component and the current q-axis reference component;

[0146] Inputting the current d-axis reference component and the current q-axis reference component into the current control link to obtain the valve side voltage d-axis reference component and the valve side voltage q-axis reference component;

[0147] By using the reference phase, the d-axis reference component of the valve side voltage and the q-axis reference component of the valve side voltage are subjected to coordinate transformation and modulation to obtain a trigger pulse signal of the inverter circuit of the energy storage power station;

[0148] The amplitude and phase of the three-phase voltage of the new energy station are adjusted by triggering pulse signals.

[0149] In some embodiments, the network control module 100 is used to actively inject a voltage signal into the faulty transmission line using the energy storage power station in the new energy station;

[0150] The fault nature determination module 200 is used to monitor the effective value of each phase voltage of the faulty transmission line after the voltage signal is injected;

[0151] Compare the effective value of each phase voltage with a preset voltage threshold;

[0152] When it is determined that the effective value of each phase voltage is greater than the preset voltage threshold, the faulty transmission line is determined to be a transient fault;

[0153] When it is determined that the effective values ​​of the voltages of each phase are not all greater than the preset voltage threshold, the faulty transmission line is determined to be a permanent fault.

[0154] In some embodiments, the voltage synchronization module 400 is used to:

[0155] Acquire a first voltage amplitude and a second voltage amplitude respectively corresponding to both sides of the station-side circuit breaker, and acquire a first voltage phase and a second voltage phase respectively corresponding to both sides of the station-side circuit breaker;

[0156] Inputting the first voltage amplitude and the second voltage amplitude into a proportional-integral controller to obtain a deviation value of the voltage amplitude, and inputting the first voltage phase and the second voltage phase into the proportional-integral controller to obtain a deviation value of the voltage phase;

[0157] The deviation value of the voltage amplitude and the deviation value of the voltage phase are respectively superimposed on the voltage d-axis component reference value in the energy storage voltage loop control and the reference phase of the energy storage network control, so that the voltage signal parameters on both sides of the station-side circuit breaker are synchronized.

[0158] In some embodiments, the system further includes: a power control module, which is used to restore the active power output before the fault after the new energy station is connected to the transmission line and the new energy station remains in an operating mode with reduced active power output for a preset period of time.

[0159] like Fig. 9 As shown, an embodiment of the present application provides an electronic device, the electronic device 10 includes a memory 20 and a processor 30, the memory 20 stores a computer program, and when the computer program is executed by the processor 30, the processor 30 executes the steps of the adaptive three-phase reclosing method for the new energy station transmission line in the above embodiment.

[0160] An embodiment of the present application provides a computer-readable storage medium having a computer program stored thereon. When the computer program is executed, the steps of the adaptive three-phase reclosing method for the new energy station transmission line in the above-mentioned embodiment are implemented.

[0161] An embodiment of the present application provides a computer program product, which includes a computer program stored on a non-transitory computer-readable storage medium, and the computer program includes program instructions. When the program instructions are executed by a computer, the computer executes the steps of the adaptive three-phase reclosing method for the new energy station transmission line in the above-mentioned embodiment.

[0162] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the above-described systems, electronic devices, computer storage media and computer program products can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0163] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0164] It should be understood that, although the various steps in the flowcharts involved in the above-mentioned embodiments are displayed in sequence according to the indication of the arrows, these steps are not necessarily executed in sequence according to the order indicated by the arrows. Unless there is a clear explanation in this article, the execution of these steps does not have a strict order restriction, and these steps can be executed in other orders. Moreover, at least a part of the steps in the flowcharts involved in the above-mentioned embodiments can include multiple steps or multiple stages, and these steps or stages are not necessarily executed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily to be carried out in sequence, but can be executed in turn or alternately with other steps or at least a part of the steps or stages in other steps.

[0165] In the several embodiments provided by the present invention, it should be understood that the disclosed systems, electronic devices, computer storage media, computer program products and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interfaces, devices or units, which can be electrical, mechanical or other forms.

[0166] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0167] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0168] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions for executing all or part of the steps of the method described in each embodiment of the present invention through a computer device (which can be a personal computer, a server, or a network device, etc.). The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (full name in English: Read-Only Memory, English abbreviation: ROM), random access memory (full name in English: Random Access Memory, English abbreviation: RAM), disk or optical disk and other media that can store program codes.

[0169] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for adaptive three-phase reclosing of a new energy station transmission line, characterized in that: The method comprises: In the event of a failure in the transmission line of the new energy station, controlling the new energy station to enter an island operation mode; By actively injecting a voltage signal into the faulty transmission line, determining whether the faulty transmission line is a transient fault; When it is determined that the faulty transmission line is the instantaneous fault, reclosing the circuit breaker on the system side; The voltage signal parameters on both sides of the station-side circuit breaker are pre-synchronized through the energy storage pre-synchronization control logic; After the pre-synchronization is completed, the circuit breaker on the station side is reclosed to switch the new energy station from the island operation mode to the operation mode connected to the transmission line.

2. The adaptive three-phase reclosing method for the transmission line of the new energy station according to claim 1 is characterized in that: Also includes: In the event of a fault in the transmission line of a new energy station, the new energy station is controlled to enter the low voltage ride-through operation mode, and then the circuit breakers on both sides of the faulty transmission line are tripped.

3. The adaptive three-phase reclosing method for the transmission line of the new energy station according to claim 1 is characterized in that: Controlling the new energy station to enter an island operation mode includes: using an energy storage power station to control the new energy station to enter an island operation mode through a droop control method; The method of controlling the new energy station to enter the island operation mode by using the energy storage power station through a droop control method includes: Obtaining active power measurement values ​​and three-phase voltage measurement values ​​of the energy storage power station; Comparing the difference between the active power measurement value and the active power reference value to obtain an active power difference; The active power difference is adjusted by using a preset droop coefficient to obtain an angular frequency; The angular frequency is transformed by a preset system angular frequency to obtain a reference frequency, and an integration operation is performed on the reference frequency to obtain a reference phase; Using the reference phase, the voltage d-axis component and the voltage q-axis component are obtained by coordinate transformation of the three-phase voltage measurement values; Comparing the voltage d-axis component and the voltage q-axis component with the reference value of the voltage d-axis component and the reference value of the voltage q-axis component respectively, and inputting the difference into a proportional-integral controller to obtain a current d-axis reference component and a current q-axis reference component; Inputting the current d-axis reference component and the current q-axis reference component into a current control link to obtain a valve-side voltage d-axis reference component and a valve-side voltage q-axis reference component; By using the reference phase, the valve side voltage d-axis reference component and the valve side voltage q-axis reference component are subjected to coordinate transformation and modulation to obtain a trigger pulse signal of an inverter circuit of an energy storage power station; The amplitude and phase of the three-phase voltage of the new energy station are adjusted by the trigger pulse signal.

4. The adaptive three-phase reclosing method for the transmission line of the new energy station according to claim 1 is characterized in that: The step of actively injecting a voltage signal into the faulty transmission line to determine whether the faulty transmission line is a transient fault comprises: Actively inject a voltage signal into the faulty transmission line by using the energy storage power station in the new energy station, and monitor the effective value of each phase voltage of the faulty transmission line after the voltage signal is injected; Comparing the effective value of each phase voltage with a preset voltage threshold; When it is determined that the effective values ​​of the voltages of each phase are greater than the preset voltage threshold, it is determined that the faulty transmission line is the instantaneous fault; When it is determined that the effective values ​​of the voltages of each phase are not all greater than the preset voltage threshold, it is determined that the faulty transmission line is a permanent fault.

5. The adaptive three-phase reclosing method for the transmission line of the new energy station according to claim 1 is characterized in that: The pre-synchronization of voltage signal parameters on both sides of the station-side circuit breaker by energy storage pre-synchronization control logic includes: Acquire a first voltage amplitude and a second voltage amplitude respectively corresponding to two sides of the station-side circuit breaker, and acquire a first voltage phase and a second voltage phase respectively corresponding to two sides of the station-side circuit breaker; Inputting the first voltage amplitude and the second voltage amplitude into a proportional-integral controller to obtain a voltage amplitude deviation value, and inputting the first voltage phase and the second voltage phase into the proportional-integral controller to obtain a voltage phase deviation value; The deviation value of the voltage amplitude and the deviation value of the voltage phase are respectively superimposed on the voltage d-axis component reference value in the energy storage voltage loop control and the reference phase of the energy storage network control, so that the voltage signal parameters on both sides of the station-side circuit breaker are synchronized.

6. The adaptive three-phase reclosing method for the transmission line of the new energy station according to claim 1 is characterized in that: Also includes: After the new energy station is connected to the transmission line, the new energy station maintains an active power reduction output operation mode for a preset period of time and then restores the active power output before the fault.

7. An adaptive three-phase reclosing system for the transmission line of a new energy station, characterized in that: The system comprises: A network control module, used to control the new energy station to enter an island operation mode when a transmission line of the new energy station fails, and actively inject a voltage signal into the faulty transmission line; A fault nature determination module, used to determine whether the faulty output line is a transient fault after actively injecting a voltage signal into the faulty output line; A first circuit breaker control module, configured to reclose the circuit breaker on the system side when it is determined that the faulty transmission line is the instantaneous fault; The voltage synchronization module is used to pre-synchronize the voltage signal parameters on both sides of the circuit breaker on the station side through the energy storage pre-synchronization control logic; The second circuit breaker control module is used to reclose the circuit breaker on the station side after completing the pre-synchronization, so that the new energy station switches from the island operation mode to the operation mode connected to the transmission line.

8. An electronic device, characterized in that: The electronic device includes a memory and a processor, wherein a computer program is stored in the memory. When the computer program is executed by the processor, the processor executes the steps of the adaptive three-phase reclosing method for the new energy station transmission line as described in any one of claims 1-6.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed, the steps of the adaptive three-phase reclosing method for the new energy station transmission line are implemented as described in any one of claims 1-6.

10. A computer program product, characterized in that The computer program product includes a computer program stored on a non-transitory computer-readable storage medium, and the computer program includes program instructions, wherein when the program instructions are executed by a computer, the computer is caused to execute the steps of the adaptive three-phase reclosing method for the new energy station transmission line as described in any one of claims 1-6.

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