CN115912358A - Grid-connected smooth switching method, device, terminal and storage medium of power distribution system - Google Patents

Abstract

The invention provides a grid-connected smooth switching method, device, terminal and storage medium of a power distribution system. The method includes: configuring a high-voltage AC distribution network, a medium-voltage AC distribution network, a medium-voltage DC distribution network, a low-voltage AC distribution network, and a low-voltage DC distribution network in the power distribution system, and configuring the medium-voltage DC distribution network with the Set up a direct/direct converter station between the low-voltage direct current distribution network, and set up a low-voltage alternating current substation between the medium-voltage alternating current distribution network and the low-voltage alternating current distribution network; monitor the operation data of the direct/direct direct current converter station and the low-voltage alternating current substation, Judging the status of the DC/DC converter station and the low-voltage AC substation according to the operating data; when the status of the DC/DC converter station is in a fault state, smoothly switch the low-voltage AC substation to supply power for the low-voltage DC distribution network; when the status of the low-voltage AC substation is In the fault state, the smooth switching DC/DC converter station supplies power to the low-voltage AC distribution network. The invention can switch smoothly in the grid-connected switching process so as to ensure the normal operation of the low-voltage distribution network.

Description

Grid-connected smooth switching method, device, terminal and storage medium of power distribution system

technical field

The invention relates to the technical field of grid-connected smooth switching, in particular to a method, device, terminal and storage medium for grid-connected smooth switching of a power distribution system.

Background technique

Roof-top distributed photovoltaic power generation has developed rapidly in recent years, and its practical applications are mostly photovoltaic power generation facilities characterized by self-consumption on the user side, surplus electricity connected to the grid, and balanced adjustment in the power distribution system. Rooftop distributed photovoltaic power generation is a new type of power generation and energy comprehensive utilization method with broad development prospects. It advocates the principles of nearby power generation, nearby grid connection, nearby conversion, and nearby use. It can not only effectively improve the power generation of photovoltaic power plants of the same scale. At the same time, it also effectively solves the problem of power loss during boosting and long-distance transportation.

However, at present, the high proportion of PV connected to the low-voltage distribution network is likely to cause the following problems: 1. Reverse power flow and voltage rise; 2. Overvoltage due to excess photovoltaic power generation during the day; 3. Photovoltaic power generation stops at night and the load is heavy Undervoltage, and fluctuates greatly due to weather during the day. In addition, the problems of voltage over-limit and power reverse caused by the high proportion of photovoltaics in the low-voltage distribution network are also prominent. In addition, in the process of grid-connected switching, unsmooth switching is prone to cause power outages and other phenomena. Once a power outage occurs, it will cause irreparable losses to the production and life of residents and society.

Contents of the invention

Embodiments of the present invention provide a method, device, terminal and storage medium for smooth grid-connected switching of a power distribution system, so as to solve the problem in the prior art that the switching is not smooth during the grid-connected switching process, resulting in power outages.

In the first aspect, an embodiment of the present invention provides a method for grid-connected smooth switching of a power distribution system, including:

In the power distribution system, a high-voltage AC distribution network, a medium-voltage AC distribution network, a medium-voltage DC distribution network, a low-voltage AC distribution network, and a low-voltage DC distribution network are configured, and the medium-voltage DC distribution network and the A DC/DC converter station is set between the low-voltage DC distribution network, and a low-voltage AC substation is set between the medium-voltage AC distribution network and the low-voltage AC distribution network;

monitoring the operation data of the DC/DC converter station and the low-voltage AC substation, and judging the states of the DC/DC converter station and the low-voltage AC substation according to the operation data;

When the state of the DC/DC converter station is in a fault state, smoothly switching the low-voltage AC substation to supply power to the low-voltage DC distribution network;

When the state of the low-voltage AC substation is a fault state, the DC/DC converter station is smoothly switched to supply power for the low-voltage AC distribution network.

In a possible implementation manner, the method for grid-connected smooth switching of the power distribution system further includes: configuring an energy storage device and an optical storage device in the power distribution system, and the energy storage device is arranged in the low-voltage DC power distribution In the network, the optical storage device is arranged in the low-voltage AC distribution network;

monitoring the device data of the energy storage device and the optical storage device, and judging the states of the energy storage device and the optical storage device according to the device data;

When the state of the optical storage device is insufficient for energy storage and the states of the DC/DC converter station and the low-voltage AC substation are in a normal state, smoothly switch the low-voltage AC substation to supply power to the low-voltage AC distribution network , the DC/DC converter station and the energy storage device supply power to the low-voltage DC distribution network;

When the state of the energy storage device is insufficient energy storage and the states of the DC/DC converter station and the low-voltage AC substation are in a normal state, smoothly switch the DC/DC converter station to the low-voltage DC substation. The grid supplies power, and the low-voltage AC substation and the optical storage device provide power for the low-voltage AC distribution network.

In a possible implementation manner, the method for grid-connected smooth switching of the power distribution system further includes:

When the state of the optical storage device and the energy storage device is sufficient energy storage and the state of the DC/DC converter station and the low-voltage AC substation is a failure state, the smooth switching of the energy storage device is The low-voltage DC distribution network supplies power, and the optical storage device supplies power for the low-voltage AC distribution network.

In a possible implementation manner, when the state of the DC/DC converter station is a fault state, smoothly switching the low-voltage AC substation to supply power to the low-voltage DC distribution network includes:

When the state of the DC/DC converter station is no-load operation, maintenance or power failure, smoothly switch the low-voltage AC substation and the optical storage device to supply power for the low-voltage AC distribution network, and the low-voltage AC distribution network The power grid and the energy storage device supply power to the low-voltage DC power distribution network.

In a possible implementation manner, when the state of the low-voltage AC substation is a fault state, smoothly switching the DC/DC converter station to supply power to the low-voltage AC distribution network includes:

When the state of the low-voltage AC substation is no-load operation, maintenance, or power failure, smoothly switch the DC/DC converter station and the energy storage device to supply power for the low-voltage DC distribution network, and the low-voltage DC distribution network The power grid and the optical storage device supply power to the low-voltage AC power distribution network.

In a possible implementation manner, a coaxial machine is set in the power distribution system;

One end of the coaxial machine is connected to the low-voltage AC distribution network through a low-voltage AC bus, and the other end of the coaxial machine is connected to the DC distribution network through a low-voltage DC bus to realize medium-voltage DC ports, DC/ Flexible sequential connection of DC converter station, coaxial machine, low voltage AC substation and medium voltage AC port.

In a possible implementation manner, when the medium-voltage DC port and the medium-voltage AC port are disconnected, the energy storage device stabilizes the low-voltage DC bus to realize DC/DC converter station, coaxial machine and low-voltage Flexible Sequential Connections in AC Substations

In the second aspect, the embodiment of the present invention provides a power distribution system grid-connected smooth switching device, in which a high-voltage AC distribution network, a medium-voltage AC distribution network, a medium-voltage DC distribution network, and a low-voltage AC distribution network are configured in the power distribution system. power grid and low-voltage DC distribution network, a DC/DC converter station is set between the medium-voltage DC distribution network and the low-voltage DC distribution network, and a DC/DC converter station is installed between the medium-voltage AC distribution network and the low-voltage AC Set up low-voltage AC substations between distribution networks, including:

A monitoring module, configured to monitor the operating data of the DC/DC converter station and the low-voltage AC substation;

A judging module, configured to judge the states of the DC/DC converter station and the low-voltage AC substation according to the operation data;

A processing module, configured to smoothly switch the low-voltage AC substation to supply power to the low-voltage DC distribution network when the state of the DC/DC converter station is a fault state; and when the state of the low-voltage AC substation is a fault state , smoothly switching the DC/DC converter station to supply power to the low-voltage AC distribution network.

In a third aspect, an embodiment of the present invention provides a terminal, including a memory, a processor, and a computer program stored in the memory and operable on the processor. When the processor executes the computer program, the The steps of the method described in the above first aspect or any possible implementation manner of the first aspect.

In a fourth aspect, an embodiment of the present invention provides a computer-readable storage medium, the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, it implements any of the above first aspect or the first aspect. Steps of the method described in a possible implementation manner.

Embodiments of the present invention provide a grid-connected smooth switching method, device, terminal, and storage medium of a power distribution system. By monitoring the operating data of the DC/DC converter station and the low-voltage AC substation, it is judged according to the operating data. The state of the DC/DC converter station and the low-voltage AC substation; when the status of the DC/DC converter station is a fault state, smoothly switch the low-voltage AC substation to supply power for the low-voltage DC distribution network; When the state of the low-voltage AC substation is a fault state, the DC/DC converter station is smoothly switched to supply power for the low-voltage AC distribution network. The present invention can switch between different power supply modes according to the operating states of the DC/DC converter station and the low-voltage AC substation, and can ensure the stability of the low-voltage DC distribution network and the low-voltage AC distribution network in real time during the switching process. In this way, the normal operation of the low-voltage distribution network is guaranteed, and the power outage accident caused by the instability of the low-voltage distribution network is avoided.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the accompanying drawings that need to be used in the descriptions of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only of the present invention. For some embodiments, those of ordinary skill in the art can also obtain other drawings based on these drawings without any creative effort.

FIG. 1 is a flow chart for realizing a method for grid-connected smooth switching of a power distribution system provided by an embodiment of the present invention;

Fig. 2 is a schematic structural diagram of a power distribution system provided by an embodiment of the present invention;

Fig. 3 is a circuit diagram of an AC/DC converter provided by an embodiment of the present invention;

Fig. 4 is the voltage waveform of the AC/DC converter circuit provided by the embodiment of the present invention;

Fig. 5 is a schematic structural view of a coaxial machine provided by an embodiment of the present invention;

Fig. 6 is a schematic structural diagram of a power distribution system grid-connected smooth switching device provided by an embodiment of the present invention;

Fig. 7 is a schematic diagram of a terminal provided by an embodiment of the present invention.

Detailed ways

In the following description, specific details such as specific system structures and technologies are presented for the purpose of illustration rather than limitation, so as to thoroughly understand the embodiments of the present invention. It will be apparent, however, to one skilled in the art that the invention may be practiced in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, devices, circuits, and methods are omitted so as not to obscure the description of the present invention with unnecessary detail.

In order to make the purpose, technical solution and advantages of the present invention clearer, specific embodiments will be described below in conjunction with the accompanying drawings.

Fig. 1 is a flow chart of the implementation of the grid-connected smooth switching method of the power distribution system provided by the embodiment of the present invention, which is described in detail as follows:

In the power distribution system, a high-voltage AC distribution network, a medium-voltage AC distribution network, a medium-voltage DC distribution network, a low-voltage AC distribution network, and a low-voltage DC distribution network are configured, and the medium-voltage DC distribution network and the A direct/direct converter station is arranged between the low-voltage direct-current distribution network, and a low-voltage alternating-current substation is arranged between the medium-voltage alternating-current distribution network and the low-voltage alternating-current distribution network.

Step 101, monitor the operation data of the DC/DC converter station and the low-voltage AC substation.

Optionally, the operation data is mainly divided into the operation data of the DC/DC converter station and the low-voltage AC substation, switch operation data, primary measurement equipment operation data, arrester operation data, DC key operation data, valve cooling system operation data, AC DC filter operation data, oil chromatography operation data, casing online monitoring operation data and infrared temperature measurement operation data.

The data during the operation of the DC/DC converter station and the low-voltage AC substation can be the pipe pressure, tap action times, oil temperature, line temperature, oil level and iron core clip current corresponding to the DC/DC converter station and low-voltage AC substation Wait for the running data.

Step 102, judging the status of the DC/DC converter station and the low-voltage AC substation according to the operating data;

Step 103, when the state of the DC/DC converter station is in the fault state, smoothly switch the low-voltage AC substation to supply power to the low-voltage DC distribution network; when the state of the low-voltage AC substation is in the fault state, smoothly switch the DC/DC converter station to low-voltage AC power distribution network.

Optionally, the fault state represents the state when the DC/DC converter station or the low-voltage AC substation has no input, and may be no-load operation, inspection or power failure.

When the state of the DC/DC converter station is no-load operation, maintenance or power failure, the low-voltage AC substation and optical storage device are smoothly switched to supply power for the low-voltage AC distribution network, and the low-voltage AC distribution network and energy storage device are used for the low-voltage DC distribution network powered by.

Optionally, an energy storage converter is provided between the low-voltage AC distribution network and the low-voltage DC distribution network, which is used to convert the energy of the optical storage device and the energy storage device, thereby balancing the low-voltage AC distribution network and the low-voltage DC distribution network. grid voltage.

Optionally, when the state of the DC/DC converter station is no-load operation, maintenance or power failure, the voltage of the low-voltage AC distribution network is maintained by the low-voltage port of the low-voltage AC substation, and the energy storage device distributes the low-voltage DC power according to the power command. The low-voltage AC distribution network supplies power to the low-voltage DC distribution network through the energy storage converter to maintain the voltage stability of the low-voltage DC distribution network. At this time, the low-voltage port of the low-voltage AC substation has the ability to switch smoothly, realizing the voltage balance between the low-voltage AC distribution network and the low-voltage DC distribution network, and providing protection for the production and life of residents and society.

When the state of the low-voltage AC substation is no-load operation, maintenance or power failure, the smooth switching DC/DC converter station and energy storage device provide power for the low-voltage DC distribution network, and the low-voltage DC distribution network and optical storage device provide power for low-voltage AC distribution Network power supply.

Optionally, when the state of the low-voltage AC substation is no-load operation, maintenance or power failure, the low-voltage port of the DC/DC converter station stabilizes the low-voltage DC bus, and the energy storage device charges and discharges the low-voltage DC distribution network according to the power command , the low-voltage AC port of the low-voltage AC busbar at the connection between the low-voltage DC distribution network and the low-voltage AC distribution network maintains the voltage of the low-voltage AC distribution network, and the photovoltaic node outputs the low-voltage AC distribution network according to its own maximum power. At this time, the direct The low-voltage port of the /DC converter needs to have the ability of smooth switching.

In a possible implementation, the method for grid-connected smooth switching of the power distribution system further includes: configuring an energy storage device and an optical storage device in the power distribution system, the energy storage device is arranged in the low-voltage DC distribution network, and the optical storage device is arranged in the low-voltage In the AC distribution network;

Monitor the device data of the energy storage device and the optical storage device, and judge the status of the energy storage device and the optical storage device according to the device data;

Optionally, the device data of the energy storage device and the optical storage device may be the voltage or electric quantity of the energy storage device and the optical storage device. When the voltage or electric quantity of the energy storage device and the optical storage device is less than a preset value, the The status of the device is Insufficient storage.

When the status of the optical storage device is insufficient energy storage and the status of the direct/direct converter station and the low-voltage AC substation is normal, the smooth switching of the low-voltage AC substation to supply power for the low-voltage AC distribution network, the direct/direct converter station and the energy storage The device supplies power for the low-voltage DC distribution network;

Optionally, when the status of the optical storage device is insufficient for energy storage and the status of the DC/DC converter station and the low-voltage AC substation is normal, the DC/DC converter station and the low-voltage AC substation have power output capabilities at the same time, and the storage The energy device can charge and discharge the low-voltage DC distribution network according to the power command. At this time, the low-voltage AC substation and the DC/DC converter station have the ability to switch smoothly.

When the state of the energy storage device is insufficient energy storage and the state of the DC/DC converter station and the low-voltage AC substation is normal, the smooth switching DC/DC converter station supplies power to the low-voltage DC distribution network, the low-voltage AC substation and the optical storage device Supplying power to the low voltage AC distribution network.

Optionally, when the status of the energy storage device is insufficient energy storage and the status of the DC/DC converter station and the low-voltage AC substation is normal, the DC/DC converter station and the low-voltage AC substation have power output capabilities at the same time. The storage device charges and discharges the low-voltage AC distribution network according to the power command. At this time, the low-voltage AC substation and the DC/DC converter station have the ability to switch smoothly.

In a possible implementation manner, the method for grid-connected smooth switching of the power distribution system further includes:

When the status of the optical storage device and the energy storage device is sufficient energy storage and the status of the DC/DC converter station and the low-voltage AC substation is a failure state, the smooth switching energy storage device supplies power to the low-voltage DC distribution network, and the optical storage device is in the low-voltage DC distribution network. AC power distribution network.

Optionally, when the state of the optical storage device and the energy storage device is sufficient energy storage and the state of the DC/DC converter station and the low-voltage AC substation is a failure state, the optical storage device and the energy storage device maintain low-voltage power distribution according to the power command At this time, both the low-voltage AC substation and the DC/DC converter station are disconnected, and the energy storage converter must have the ability to maintain the voltage of the low-voltage AC bus and the voltage of the low-voltage DC bus at the same time.

As shown in Figure 2, the structure diagram of the power distribution system, the grid-connected smooth switching system of the power distribution system includes: a high-voltage AC distribution network 10, a medium-voltage AC distribution network 11, a medium-voltage DC distribution network 12, and a low-voltage DC distribution network. Network 13, low-voltage AC distribution network 14, substation 20, low-voltage AC substation 21, AC/DC converter station 22, DC/DC converter station 23, energy storage device 24, optical storage device 25, and DC/DC converter 26 ;

The output end of the high-voltage AC distribution network 10 is connected to the input end of the transformer 20 through the high-voltage AC branch circuit, and the output end of the transformer 20 is connected to the input end of the medium-voltage AC distribution network 11 through the high-voltage AC branch circuit, and the medium-voltage AC distribution network 11 The output end of the AC/DC converter 22 is connected to the input end of the AC/DC converter 22 through the medium voltage AC branch, and the output end of the AC/DC converter 22 is connected to the input end of the medium voltage DC distribution network 12 through the medium voltage DC branch circuit;

The output end of the medium-voltage AC distribution network 11 is connected to the input end of the low-voltage AC substation 21 through the low-voltage AC busbar, and the output end of the low-voltage AC substation 21 is connected to the input end of the low-voltage AC distribution network 14 through the low-voltage AC busbar. The output end of the network 12 is connected to the input end of the DC/DC converter 23 through the medium-voltage DC bus, and the output end of the DC/DC converter 23 is connected to the input end of the low-voltage DC distribution network 13 through the low-voltage DC bus;

The output end of the low-voltage AC distribution network 14 is connected to the input end of the AC/DC converter 22 through the low-voltage AC branch, and the output end of the AC/DC converter 22 is connected to the input of the low-voltage DC distribution network 13 through the low-voltage DC branch The output terminal of the low-voltage DC distribution network 13 is connected to the input terminal of the DC/converter 26 through the low-voltage DC branch circuit, and the output terminal of the DC/converter 26 is connected to the input terminal of the low-voltage AC distribution network 14 through the low-voltage AC branch circuit. end;

The output end of the energy storage device 24 is connected to the input end of the low-voltage DC distribution network 13 through a low-voltage DC bus;

The output end of the optical storage device 25 is connected to the input end of the DC/converter 26 through the low-voltage AC branch, and the output end of the DC/converter 26 is connected to the input end of the low-voltage AC distribution network 14 through the low-voltage AC branch.

In a possible implementation manner, a coaxial machine is set in the power distribution system;

Optionally, the coaxial motor is coaxially connected to the three-phase AC motor and the DC motor. Configuring the coaxial motor in the power distribution system can generate a proportional control technology for the voltage of the AC port and the DC port, thereby avoiding the problem of not being able to switch smoothly.

The invention makes the ratio control technology of AC port and DC port voltage clearer by comparing and analyzing the AC/DC converter and the coaxial machine.

Optionally, referring to the AC/DC converter circuit diagram shown in Figure 3 and the voltage waveform shown in Figure 4, it can be obtained that the AC/DC converter adopts a three-phase bridge rectifier circuit, and the three-phase bridge rectifier circuit consists of six During the period from t ₁ to t ₂ , the potential of point e _a in the common cathode group is the highest, S ₁ is turned on, and the potential of point e _b in the common anode is the lowest, and S ₄ is turned on. At this time, the path through which the current flows is u _a ->e _a ->S ₁ ->u _D ->S ₄ ->e _b ->u _b , and the voltage at the DC port is the line voltage u _a -u _b ;

During the period from t ₂ to t ₃ , the potential of point e _a in the common cathode group is the highest, S ₁ is turned on, and the potential of point e _c in the common anode group is the lowest, and S ₆ is turned on. At this time, the path through which the current flows is u _a ->e _a ->S ₁ ->u _D ->S ₆ ->e _c ->u _c , and the voltage at the DC port is the line voltage u _a -u _c ;

During the period from t ₃ to t ₄ , the potential of point e _b in the common cathode group is the highest, S ₃ is turned on, and the potential of point e _c in the common anode group is the lowest, and S ₆ is turned on. At this time, the current flows through u _b ->e _b ->S ₃ ->u _D ->S ₆ ->e _c ->u _c , and the voltage at the DC port is the line voltage u _b -u _c .

Optionally, the conduction diode is judged by the potential level, and then the path of the current flow is obtained, so as to realize the proportional control of the voltage of the AC port and the voltage of the DC port.

The structural diagram of the coaxial machine shown in Figure 5, from the perspective of the AC-DC interface converter, the voltage state equation can be expressed as:

u_a、u_b和u_c分别表示交流输入端口的相电压，

和

分别表示三相旋转磁动势，i_a、i_b和i_c分别表示三相电流，e_a、e_b和e_c分别表示三相电动势，r_ai_a、r_bi_b和r_ci_c分别表示三相线路降压，t表示当前时间。

u _a , u _b and u _c represent the phase voltages of the AC input port respectively,

and

represent the three-phase rotating magnetomotive force respectively, _ia , i _b and i _c represent the three-phase current respectively, e _a , e _b and e _c represent the three-phase electromotive force respectively, r _a i _a , r _b i _b and r _c i _c respectively represent three-phase line step-down, t represents the current time.

The dq axis components are obtained through the Parker transformation, and the Parker transformation matrix is:

Where C _T represents the Parker transformation matrix, θ represents the current vector position, t ₀ represents the initial time, ω represents the rotational speed of the vector, and θ ₀ represents the initial vector position.

得到dq轴分量；according to

Get the dq axis components;

Among them, u _d represents the direct-axis voltage, u _q represents the quadrature-axis voltage, L represents the inductance, i _q represents the quadrature-axis current, _id represents the direct-axis current, r _d i _d represents the direct-axis line step-down, r _q i _q represents Quadrature axis line step-down, _ed means direct axis electromotive force, e _q means quadrature axis electromotive force.

From the perspective of the coaxial machine, the dq axis components can be written as:

Among them, e _md represents the direct axis modulation electromotive force, and ω _m represents the rotational speed of the modulation rotation vector.

Therefore, to realize the coaxial machine control of the AC-DC interface converter, the direct-axis component _ed = e _md of the induced electromotive force is set to 0, the quadrature-axis component e _q = e _mq , and the AC-DC interface converter is equivalent to the coaxial Write the governing equations for the motor:

其中，e_mq表示交轴调制电动势。

Among them, _emq represents the quadrature axis modulation electromotive force.

Connect one end of the coaxial machine to the low-voltage AC distribution network through the low-voltage AC busbar, and connect the other end of the coaxial machine to the DC distribution network through the low-voltage DC busbar to realize medium-voltage DC ports, DC/DC converter stations, and coaxial machine , flexible sequential connection of low-voltage AC substations and medium-voltage AC ports.

After the coaxial machine control is realized, the voltage amplitude of the AC and DC ports is proportional, so the low-voltage distribution network realizes the effect of parallel connection of multiple sets of coaxial machines at the port of the energy storage converter, which is equivalent to connecting the AC low voltage bus with an AC and DC coaxial machine and DC low-voltage busbars, realizing the flexible connection of medium-voltage DC ports, DC/DC converter stations, coaxial machines, low-voltage AC substations and medium-voltage AC ports, so only one voltage port has a rigid voltage source, and the low-voltage power distribution The voltage of the network is stable, and the smooth switching function is realized.

In a possible implementation, when the medium-voltage DC port and the medium-voltage AC port are disconnected, the energy storage device stabilizes the low-voltage DC bus, and realizes the flexible sequential connection of the DC/DC converter station, the coaxial machine and the low-voltage AC substation.

Optionally, when the medium-voltage DC port and the medium-voltage AC port are disconnected, the energy storage converter stabilizes the low-voltage DC bus to form a flexible connection between the DC/DC converter station, the coaxial machine and the low-voltage AC substation. If the energy converter has sufficient capacity, the voltage of the low-voltage distribution network will be stable and the smooth switching function will be realized.

An embodiment of the present invention provides a grid-connected smooth switching method of a power distribution system, by monitoring the operation data of the DC/DC converter station and the low-voltage AC substation, and judging the status of the DC/DC converter station and the low-voltage AC substation according to the operating data ; When the state of the DC/DC converter station is in the fault state, the smooth switching low-voltage AC substation is used to supply power to the low-voltage DC distribution network; Grid powered. The present invention can switch different power supply modes according to the operating status of the DC/DC converter station and the low-voltage AC substation, and can ensure the stability of the low-voltage DC distribution network and the low-voltage AC distribution network in real time during the switching process, thereby ensuring The normal operation of the low-voltage distribution network avoids power outage accidents caused by the instability of the low-voltage distribution network. In addition, a coaxial machine is set between the two ports of the energy storage converter, and the control between the two ports has the characteristics of a synchronous machine to realize medium-voltage DC ports, DC/DC converter stations, coaxial machines, and low-voltage AC substations. Flexible connections to medium voltage AC ports.

It should be understood that the sequence numbers of the steps in the above embodiments do not mean the order of execution, and the execution order of each process should be determined by its functions and internal logic, and should not constitute any limitation to the implementation process of the embodiment of the present invention.

The following are device embodiments of the present invention. For details that are not exhaustively described therein, reference may be made to the corresponding method embodiments above.

Fig. 6 shows a schematic structural diagram of a power distribution system grid-connected smooth switching device provided by an embodiment of the present invention. For the convenience of description, only the parts related to the embodiment of the present invention are shown, and the details are as follows:

As shown in Figure 6, a high-voltage AC distribution network, a medium-voltage AC distribution network, a medium-voltage DC distribution network, a low-voltage AC distribution network, and a low-voltage DC distribution network are configured in the power distribution system. A DC/DC converter station is set between the grid and the low-voltage DC distribution network, and a low-voltage AC substation is set between the medium-voltage DC distribution network and the low-voltage DC distribution network. The distribution system grid-connected smooth switching device 60 includes:

The monitoring module 61 is used to monitor the operation data of the DC/DC converter station and the low-voltage AC substation;

A judging module 62, configured to judge the states of the DC/DC converter station and the low-voltage AC substation according to the operating data;

The processing module 63 is used to smoothly switch the low-voltage AC substation to supply power to the low-voltage DC distribution network when the state of the direct/direct converter station is in a fault state; The flow station supplies power to the low-voltage AC distribution network.

In a possible implementation, an energy storage device and an optical storage device are configured in the power distribution system, the energy storage device is arranged in a low-voltage DC distribution network, the optical storage device is arranged in a low-voltage AC distribution network, and the monitoring module 61 also Device data for monitoring energy storage devices and optical storage devices;

The judging module 62 is also used to judge the states of the energy storage device and the optical storage device according to the device data;

The processing module 63 is also used to smoothly switch the low-voltage AC substation to supply power to the low-voltage AC distribution network when the state of the optical storage device is insufficient for energy storage and the states of the direct/direct converter station and the low-voltage AC substation are normal. The converter station and the energy storage device supply power to the low-voltage DC distribution network; and when the status of the energy storage device is insufficient energy storage and the status of the DC/DC converter station and the low-voltage AC substation is in a normal state, smooth switching of the direct/direct conversion The flow station supplies power to the low-voltage DC distribution network, and the low-voltage AC substation and optical storage device supply power to the low-voltage AC distribution network.

In a possible implementation, the processing module 63 is also used to smoothly switch the energy storage device and the energy storage device when the state of the optical storage device and the energy storage device is sufficient and the state of the DC/DC converter station and the low-voltage AC substation is a fault state. The energy device supplies power to the low-voltage DC distribution network, and the optical storage device supplies power to the low-voltage AC distribution network.

In a possible implementation, the processing module 63 smoothly switches the low-voltage AC substation to supply power to the low-voltage DC distribution network when the state of the DC/DC converter station is in a fault state, for:

When the state of the DC/DC converter station is no-load operation, maintenance or power failure, the low-voltage AC substation and optical storage device are smoothly switched to supply power for the low-voltage AC distribution network, and the low-voltage AC distribution network and energy storage device are used for the low-voltage DC distribution network powered by.

In a possible implementation, the processing module 63 smoothly switches the DC/DC converter station to supply power to the low-voltage AC distribution network when the status of the low-voltage AC substation is in a fault state, for:

When the state of the low-voltage AC substation is no-load operation, maintenance or power failure, the smooth switching DC/DC converter station and energy storage device provide power for the low-voltage DC distribution network, and the low-voltage DC distribution network and optical storage device provide power for low-voltage AC distribution Network power supply.

In a possible implementation, a coaxial machine is set in the power distribution system;

Connect one end of the coaxial machine to the low-voltage AC distribution network through the low-voltage AC busbar, and connect the other end of the coaxial machine to the DC distribution network through the low-voltage DC busbar to realize medium-voltage DC ports, DC/DC converter stations, and coaxial machine , flexible sequential connection of low-voltage AC substations and medium-voltage AC ports.

In a possible implementation, when the medium-voltage DC port and the medium-voltage AC port are disconnected, the energy storage device stabilizes the low-voltage DC bus, and realizes the flexible sequential connection of the DC/DC converter station, the coaxial machine and the low-voltage AC substation .

The embodiment of the present invention provides a power distribution system grid-connected smooth switching device, by monitoring the operation data of the DC/DC converter station and the low-voltage AC substation, and judging the status of the DC/DC converter station and the low-voltage AC substation according to the operating data ; When the state of the DC/DC converter station is in the fault state, the smooth switching low-voltage AC substation is used to supply power to the low-voltage DC distribution network; Grid powered. The present invention can switch different power supply modes according to the operating status of the DC/DC converter station and the low-voltage AC substation, and can ensure the stability of the low-voltage DC distribution network and the low-voltage AC distribution network in real time during the switching process, thereby ensuring The normal operation of the low-voltage distribution network avoids power outage accidents caused by the instability of the low-voltage distribution network. In addition, a coaxial machine is set between the two ports of the energy storage converter, and the control between the two ports has the characteristics of a synchronous machine to realize medium-voltage DC ports, DC/DC converter stations, coaxial machines, and low-voltage AC substations. Flexible connections to medium voltage AC ports.

Fig. 7 is a schematic diagram of a terminal provided by an embodiment of the present invention. As shown in FIG. 7 , the terminal 7 of this embodiment includes: a processor 70 , a memory 71 and a computer program 72 stored in the memory 71 and operable on the processor 70 . When the processor 70 executes the computer program 72, it realizes the steps in the above-mentioned embodiments of the grid-connected smooth switching method of the power distribution system, for example, steps 101 to 103 shown in FIG. 1 . Alternatively, when the processor 70 executes the computer program 72, it realizes the functions of the modules/units in the above-mentioned device embodiments, such as the functions of the modules/units 61 to 63 shown in FIG. 6 .

Exemplarily, the computer program 72 can be divided into one or more modules/units, and one or more modules/units are stored in the memory 71 and executed by the processor 70 to implement the present invention. One or more modules/units may be a series of computer program instruction segments capable of accomplishing specific functions, and the instruction segments are used to describe the execution process of the computer program 72 in the terminal 7 . For example, the computer program 72 may be divided into modules/units 61 to 63 shown in FIG. 6 .

The terminal 7 may include, but not limited to, a processor 70 and a memory 71 . Those skilled in the art can understand that FIG. 7 is only an example of the terminal 7 and does not constitute a limitation to the terminal 7. It may include more or less components than those shown in the illustration, or combine certain components, or different components, such as Terminals may also include input and output devices, network access devices, buses, and so on.

The so-called processor 70 can be a central processing unit (Central Processing Unit, CPU), and can also be other general-purpose processors, digital signal processors (Digital Signal Processor, DSP), application specific integrated circuits (Application Specific Integrated Circuit, ASIC), Field-Programmable Gate Array (Field-Programmable Gate Array, FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor, or the processor may be any conventional processor, or the like.

The storage 71 may be an internal storage unit of the terminal 7, such as a hard disk or a memory of the terminal 7. The memory 71 can also be an external storage device of the terminal 7, such as a plug-in hard disk equipped on the terminal 7, a smart memory card (Smart MediaCard, SMC), a secure digital (Secure Digital, SD) card, a flash memory card (Flash Card), etc. . Further, the memory 71 may also include both an internal storage unit of the terminal 7 and an external storage device. The memory 71 is used to store computer programs and other programs and data required by the terminal. The memory 71 can also be used to temporarily store data that has been output or will be output.

Those skilled in the art can clearly understand that for the convenience and brevity of description, only the division of the above-mentioned functional units and modules is used for illustration. In practical applications, the above-mentioned functions can be assigned to different functional units, Completion of modules means that the internal structure of the device is divided into different functional units or modules to complete all or part of the functions described above. Each functional unit and module in the embodiment may be integrated into one processing unit, or each unit may exist separately physically, or two or more units may be integrated into one unit, and the above-mentioned integrated units may adopt hardware It can also be implemented in the form of software functional units. In addition, the specific names of the functional units and modules are only for the convenience of distinguishing each other, and are not used to limit the protection scope of the present application. For the specific working process of the units and modules in the above system, reference may be made to the corresponding process in the foregoing method embodiments, and details will not be repeated here.

In the above-mentioned embodiments, the descriptions of each embodiment have their own emphases, and for parts that are not detailed or recorded in a certain embodiment, refer to the relevant descriptions of other embodiments.

Those skilled in the art can appreciate that the units and algorithm steps of the examples described in conjunction with the embodiments disclosed herein can be implemented by electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are executed by hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art may use different methods to implement the described functions for each specific application, but such implementation should not be regarded as exceeding the scope of the present invention.

In the embodiments provided in the present invention, it should be understood that the disclosed device/terminal and method may be implemented in other ways. For example, the device/terminal embodiments described above are only illustrative. For example, the division of modules or units is only a logical function division. There may be other division methods in actual implementation. For example, multiple units or components can be Incorporation may either be integrated into another system, or some features may be omitted, or not implemented. In another point, the mutual coupling or direct coupling or communication connection shown or discussed may be through some interfaces, and the indirect coupling or communication connection of devices or units may be in electrical, mechanical or other forms.

A unit described as a separate component may or may not be physically separated, and a component displayed as a unit may or may not be a physical unit, that is, it may be located in one place, or may be distributed to multiple network units. Part or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

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

If an integrated module/unit is realized in the form of a software function unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the present invention realizes all or part of the processes in the methods of the above embodiments, and can also be completed by instructing related hardware through computer programs, and the computer programs can be stored in a computer-readable storage medium. When executed by the processor, the steps in the embodiments of the above-mentioned grid-connected smooth switching method of the power distribution system can be realized. Wherein, the computer program includes computer program code, and the computer program code may be in the form of source code, object code, executable file or some intermediate form. The computer-readable medium may include: any entity or device capable of carrying computer program code, recording medium, U disk, removable hard disk, magnetic disk, optical disk, computer memory, read-only memory (Read-Only Memory, ROM), random access Memory (Random Access Memory, RAM), electrical carrier signal, telecommunication signal and software distribution medium, etc.

The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: it can still be described in the foregoing embodiments Modifications to the technical solutions recorded, or equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of each embodiment of the present invention, and should be included in the scope of the present invention. within the scope of protection.

Claims (10)

1. A grid-connected smooth switching method for a power distribution system is characterized by comprising the following steps: configuring a high-voltage alternating-current power distribution network, a medium-voltage direct-current power distribution network, a low-voltage alternating-current power distribution network and a low-voltage direct-current power distribution network in a power distribution system, arranging a direct/direct-current converter station between the medium-voltage direct-current power distribution network and the low-voltage direct-current power distribution network, and arranging a low-voltage alternating-current transformer substation between the medium-voltage alternating-current power distribution network and the low-voltage alternating-current power distribution network;

monitoring operation data of the direct/direct current converter station and the low-voltage alternating current transformer substation, and judging the states of the direct/direct current converter station and the low-voltage alternating current transformer substation according to the operation data;

when the state of the direct current/direct current converter station is a fault state, smoothly switching the low-voltage alternating current transformer substation to supply power to the low-voltage direct current distribution network;

and when the state of the low-voltage alternating-current transformer substation is a fault state, smoothly switching the direct/direct current converter station to supply power to the low-voltage alternating-current power distribution network.

2. The grid-connected smooth switching method of the power distribution system according to claim 1, further comprising: configuring an energy storage device and an optical storage device in the power distribution system, wherein the energy storage device is arranged in the low-voltage direct current power distribution network, and the optical storage device is arranged in the low-voltage alternating current power distribution network;

monitoring device data of the energy storage device and the optical storage device, and judging the states of the energy storage device and the optical storage device according to the device data;

when the state of the optical storage device is insufficient energy storage and the states of the direct current/direct current converter station and the low-voltage alternating current transformer substation are normal states, the low-voltage alternating current transformer substation is switched smoothly to supply power to the low-voltage alternating current power distribution network, and the direct current/direct current converter station and the energy storage device supply power to the low-voltage direct current power distribution network;

when the state of the energy storage device is insufficient energy storage and the states of the direct current/direct current converter station and the low-voltage alternating current transformer substation are normal states, the direct current/direct current converter station is switched smoothly to supply power to the low-voltage direct current power distribution network, and the low-voltage alternating current transformer substation and the light device supply power to the low-voltage alternating current power distribution network.

3. The grid-connected smooth switching method of the power distribution system according to any one of claims 1 to 2, further comprising:

when the states of the optical storage device and the energy storage device are sufficient in energy storage and the states of the direct current/direct current converter station and the low-voltage alternating current transformer station are fault states, the energy storage device is switched smoothly to supply power to the low-voltage direct current power distribution network, and the optical storage device supplies power to the low-voltage alternating current power distribution network.

4. The grid-connected smooth switching method of the power distribution system according to claim 3, wherein when the state of the DC/DC converter station is a fault state, smoothly switching the low-voltage AC substation to supply power to the low-voltage DC distribution network comprises:

and when the DC/DC converter station is in a no-load operation, maintenance or power failure state, smoothly switching the low-voltage AC transformer substation and the optical device to supply power to the low-voltage AC power distribution network, and supplying power to the low-voltage DC power distribution network by the low-voltage AC power distribution network and the energy storage device.

5. The grid-connected smooth switching method of the power distribution system according to claim 4, wherein when the state of the low-voltage ac substation is a fault state, smoothly switching the dc/dc converter station to supply power to the low-voltage ac power distribution network comprises:

when the low-voltage alternating-current transformer substation is in no-load operation, maintenance or power failure, the direct/direct-current converter station and the energy storage device are switched smoothly to supply power to the low-voltage direct-current power distribution network, and the low-voltage direct-current power distribution network and the light device supply power to the low-voltage alternating-current power distribution network.

6. The grid-connected smooth switching method of the power distribution system according to claim 2, characterized in that a coaxial machine is arranged in the power distribution system;

and one end of the coaxial machine is connected with the low-voltage alternating-current power distribution network through a low-voltage alternating-current bus, and the other end of the coaxial machine is connected with the direct-current power distribution network through a low-voltage direct-current bus, so that flexible sequential connection of a medium-voltage direct-current port, a direct/direct-current converter station, the coaxial machine, a low-voltage alternating-current transformer substation and a medium-voltage alternating-current port is realized.

7. The power distribution system grid-connection smooth switching method according to claim 6, wherein when the medium-voltage direct-current port and the medium-voltage alternating-current port are disconnected, the energy storage device stabilizes a low-voltage direct-current bus, and flexible sequential connection of the direct/direct-current converter station, the coaxial machine and the low-voltage alternating-current substation is achieved.

8. A power distribution system grid-connected smooth switching device is characterized in that a high-voltage alternating-current power distribution network, a medium-voltage direct-current power distribution network, a low-voltage alternating-current power distribution network and a low-voltage direct-current power distribution network are configured in a power distribution system, a direct/direct-current converter station is arranged between the medium-voltage direct-current power distribution network and the low-voltage direct-current power distribution network, and a low-voltage alternating-current transformer substation is arranged between the medium-voltage alternating-current power distribution network and the low-voltage alternating-current power distribution network; the grid-connected smooth switching device of the power distribution system comprises:

the monitoring module is used for monitoring the operation data of the direct/direct current converter station and the low-voltage alternating current transformer station;

the judging module is used for judging the states of the direct/direct current converter station and the low-voltage alternating current transformer substation according to the operation data;

the processing module is used for smoothly switching the low-voltage alternating-current transformer substation to supply power to the low-voltage direct-current power distribution network when the state of the direct/direct-current converter station is a fault state; and when the state of the low-voltage alternating-current transformer substation is a fault state, smoothly switching the direct/direct current converter station to supply power to the low-voltage alternating-current power distribution network.

9. A terminal comprising a memory for storing a computer program and a processor for invoking and executing the computer program stored in the memory, characterized in that the processor when executing the computer program implements the steps of the method according to any of the preceding claims 1 to 7.

10. A computer-readable storage medium, in which a computer program is stored which, when being executed by a processor, carries out the steps of the method according to any one of claims 1 to 7.

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