CN114188971A

CN114188971A - Photovoltaic box-type substation

Info

Publication number: CN114188971A
Application number: CN202111344235.9A
Authority: CN
Inventors: 邓丽文; 许凯旋; 喻金; 于建军; 陈绍庆; 余恩赐; 许斌斌; 陈星燃; 胡日鹏; 夏铭聪; 江永健; 韩畅; 李成
Original assignee: Guangzhou Electric Power Engineering Design Institute Co ltd; Guangzhou Power Supply Bureau of Guangdong Power Grid Co Ltd; Haihong Electric Co Ltd
Current assignee: Guangzhou Electric Power Engineering Design Institute Co ltd; Guangzhou Power Supply Bureau of Guangdong Power Grid Co Ltd; Haihong Electric Co Ltd
Priority date: 2021-11-10
Filing date: 2021-11-10
Publication date: 2022-03-15

Abstract

The invention discloses a box-type transformer substation, which is applied to a photovoltaic power generation system and comprises: a photovoltaic power module; the input end of the inverter is connected with the photovoltaic power supply assembly; the input port of the distribution room is connected with the output end of the inverter; the grid-connected circuit breaker is arranged on a circuit between the inverter and the power distribution room, and is provided with a mains supply fault induction piece which is connected with a target power grid. When the target power grid loses power, the commercial power fault induction component in the grid-connected circuit breaker acts to cause the grid-connected circuit breaker to trip, so that a circuit between the inverter and the power distribution room is disconnected, and therefore under the condition that the target power grid loses power, the grid-connected circuit breaker trips, the inverter loses load, the photovoltaic power supply component is separated from a closed loop, power generation is stopped, the safety performance of the box-type substation is improved, and potential safety hazards caused by the fact that the photovoltaic panel can still continuously operate and continue to supply power to the whole box-type substation when the power grid loses power are eliminated.

Description

Photovoltaic box-type substation

Technical Field

The invention relates to the field of photovoltaic power generation, in particular to a photovoltaic box-type substation.

Background

With the improvement of living standard of people, people pay more and more attention to photovoltaic power generation, and clean energy such as solar energy becomes the first choice of people.

The box-type substation is also called a pre-installed substation or a pre-installed substation. The high-voltage switch equipment, the distribution transformer and the low-voltage distribution device are arranged into a whole according to a certain wiring scheme, and the factory prefabricated indoor and outdoor compact distribution equipment is provided. The box-type transformer substation is suitable for mines, factory enterprises, oil and gas fields, wind power and photovoltaic power stations, replaces the original civil power distribution room and power distribution station, and becomes a novel complete set of power transformation and distribution device.

In a photovoltaic power generation system, a box-type substation integrates equipment such as a low-voltage cabinet, a transformer and a high-voltage cabinet into a steel structure container, and provides a highly integrated transformation and distribution electrolytic solution for a medium-voltage grid-connected scene of a photovoltaic ground power station. The box-type substation is characterized in that the solar cell array is arranged on the top, and a transformer is arranged in the substation and serves as a power distribution device.

When the photovoltaic power generation system normally operates, the photovoltaic power supply assembly converts solar energy into direct current, then the direct current is converted into alternating current through the inverter, and the alternating current is subjected to boosting treatment and grid-connected connection of the distribution room. However, when the transmission line of the target power grid fails, the photovoltaic panel may still be in a continuous operation state, and the photovoltaic power supply assembly continues to supply power to the whole box-type substation. This phenomenon not only causes damage to the photovoltaic power generation system, but also creates a serious potential safety hazard, which is very dangerous for the workers who maintain and overhaul the box-type substation.

Disclosure of Invention

The present invention is directed to solving at least one of the problems of the prior art. Therefore, the photovoltaic box-type substation provided by the invention can ensure that the power transmission line between the photovoltaic power supply assembly and the distribution room can be timely disconnected after the box-type substation is powered off, so that the photovoltaic substation is safer to use while the power generation system is protected.

According to a first aspect of the invention, a box-type substation is applied to a photovoltaic power generation system, and comprises:

a photovoltaic power module;

the input end of the inverter is connected with the photovoltaic power supply assembly and is used for converting direct current led in by the photovoltaic power supply assembly into alternating current;

the input end of the power distribution room is connected with the output end of the inverter and used for distributing electric energy to be merged into a target power grid;

and the grid-connected circuit breaker is arranged in a circuit between the inverter and the power distribution room, and is provided with a mains supply fault induction piece, and the mains supply fault induction piece is connected with the target power grid and is used for detecting that the target power grid causes tripping of the grid-connected circuit breaker after power failure.

The box-type substation provided by the embodiment of the invention at least has the following beneficial effects:

when the photovoltaic power generation system normally operates, the photovoltaic power supply assembly converts solar energy into direct current and transmits the direct current to the inverter, the inverter converts the direct current into alternating current and then inputs the alternating current into the grid-connected metering box, the grid-connected metering box meters the input electric energy, then the current flows into the distribution room from the grid-connected metering box and then is merged into a target power grid, and the current flows into the distribution room from the inverter and is connected to the grid-connected circuit breaker. When the target power grid loses power, the commercial power fault induction component in the grid-connected circuit breaker acts to cause the grid-connected circuit breaker to trip, so that a circuit between the inverter and the power distribution room is disconnected, and therefore under the condition that the target power grid loses power, the grid-connected circuit breaker trips, the inverter loses load, the photovoltaic power supply component is separated from a closed loop, power generation is stopped, the safety performance of the box-type substation is improved, the potential safety hazard generated by continuous operation of the photovoltaic panel after the power grid loses power and continuous power transmission of the whole box-type substation is eliminated.

Optionally, according to some embodiments of the invention, the mains fault sensing element is a mains voltage loss release

Optionally, according to some embodiments of the present invention, the distribution room is provided with an incoming line breaker, the incoming line breaker is connected to the grid-connected breaker through a safety interlock, and the safety interlock is configured to perform a tripping operation on the grid-connected breaker when the incoming line breaker performs a protection operation.

Optionally, according to some embodiments of the present invention, the distribution room is equipped with a safety automatic device, and the safety automatic device is connected to the incoming line breaker and the target power grid, and is configured to perform stable control on the photovoltaic power generation system in a dynamic process after the target power grid fails.

Optionally, according to some embodiments of the present invention, an anti-islanding protection device is disposed inside the inverter, and the anti-islanding protection device is connected to the target power grid and configured to disconnect a circuit between the inverter and the photovoltaic power supply assembly after the target power grid loses power.

Optionally, according to some embodiments of the present invention, the anti-islanding protection device includes:

the island detection module is connected to the target power grid and used for detecting whether the target power grid loses power or not;

the operating switch is arranged in a circuit between the photovoltaic power supply assembly and the target power grid and is used for disconnecting a circuit for transmitting alternating current to the power distribution room by the inverter after the target power grid loses power;

and the control module is connected with the island detection module and the operating switch and is used for controlling the operating switch to be switched off after a first time interval after the island detection module judges that the power grid side loses power.

Optionally, according to some embodiments of the present invention, the switching device further includes a first switching-on component, disposed in a circuit between the target power grid and the operating switch, and configured to switch on the operating switch after a second time interval elapses after the voltage of the target power grid is recovered.

Optionally, according to some embodiments of the present invention, a second closing assembly is included, where the second closing assembly is connected to a circuit between the target power grid and a closing coil of the grid-connected circuit breaker, and is configured to close the grid-connected circuit breaker after a third time interval elapses after the voltage of the target power grid is recovered.

Optionally, according to some embodiments of the present invention, the box-type substation includes a grid-connected metering cabinet, the grid-connected metering cabinet is provided with an electric energy meter and a load control device, the load control device is connected to the inverter, the electric energy meter is connected to the load control device, and the grid-connected breaker is disposed between the electric energy meter and the distribution room.

Optionally, according to some embodiments of the present invention, the grid-connected circuit breaker employs a double-in double-out molded case air switch.

Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.

Drawings

The above and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

fig. 1 is a schematic connection diagram of a box-type substation according to an embodiment of the present invention;

FIG. 2 is a schematic circuit diagram according to an embodiment of the present invention;

fig. 3 is a schematic connection diagram of a grid-connected point circuit breaker according to an embodiment of the present invention;

FIG. 4 is an internal schematic diagram of an inverter in an embodiment of the invention;

fig. 5 is an internal schematic diagram of an anti-islanding protection device according to an embodiment of the present invention;

FIG. 6 is a circuit diagram of the transformer cabinet and the high-voltage cabinet according to the embodiment of the invention;

fig. 7 is a circuit diagram of the interior of the low-voltage cabinet according to the embodiment of the invention.

Reference numerals:

the box-type substation 100 is provided with,

photovoltaic module 110, solar array 111, combiner box 112,

the control system comprises an inverter 120, an inverter circuit 121, a filter circuit 122, an anti-islanding protection device 123, an islanding detection module 1231, a control module 1232, an operation switch 1233, a first closing component 1234,

a grid-connected metering cabinet 130, a load control device 131, an electric energy meter 132, a grid-connected circuit breaker 133, a mains failure sensor 1331, a second closing assembly 134,

the power distribution room 140, the low-voltage cabinet 141, the low-voltage incoming cabinet 1411, the low-voltage outgoing cabinet 1412, the low-voltage compensation cabinet 1413, the interconnection cabinet 1414, the transformer cabinet 142, the high-voltage cabinet 143, the input port 144, the incoming line breaker 145, the safety automatic device 146,

a target grid 150, a grid live line 151, a grid neutral line 152,

in fig. 6 and 7, the A end is connected with the A1 end, and the B end is connected with the B1 end.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the accompanying drawings are illustrative only for the purpose of explaining the present invention, and are not to be construed as limiting the present invention.

In the description of the present invention, it should be understood that the orientation or positional relationship referred to in the description of the orientation, such as the upper, lower, front, rear, left, right, etc., is based on the orientation or positional relationship shown in the drawings, and is only for convenience of description and simplification of description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention.

In the description of the present invention, the meaning of a plurality of means is one or more, the meaning of a plurality of means is two or more, and larger, smaller, larger, etc. are understood as excluding the number, and larger, smaller, inner, etc. are understood as including the number. If the first and second are described for the purpose of distinguishing technical features, they are not to be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated or implicitly indicating the precedence of the technical features indicated.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an illustrative embodiment," "an example," "a specific example," or "some examples" or the like mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

In the description of the present invention, unless otherwise explicitly limited, terms such as arrangement, installation, connection and the like should be understood in a broad sense, and those skilled in the art can reasonably determine the specific meanings of the above terms in the present invention in combination with the specific contents of the technical solutions.

The photovoltaic grid-connected power generation system in China mainly comprises a solar cell array, a junction box, an inverter, a step-up transformer, a low-voltage alternating current power distribution cabinet, a power distribution cabinet and a high-voltage switch. The power distribution cabinet, the inverter, the step-up transformer and the high-voltage switch equipment belong to a power transformation grid-connected part.

In a photovoltaic power generation system, a header box, a low-voltage cabinet, a transformer, a high-voltage cabinet and other equipment are integrated into a steel structure container in a box-type substation, and a highly integrated transformation and distribution electrolytic solution is provided for a medium-voltage grid-connected scene of a photovoltaic ground power station. The distributed box type transformer substation is characterized in that the solar cell array is installed on the top, and a transformer is arranged inside the transformer substation and serves as a power distribution device. However, after the power grid loses power, the photovoltaic panel may still be in a continuous operation state to continue to supply power to the whole box-type substation, and a serious potential safety hazard exists in the process, which is very dangerous for workers who maintain and overhaul the box-type substation.

The present invention is directed to solving at least one of the problems of the prior art. Therefore, the photovoltaic box-type substation provided by the invention can ensure that a power transmission line between a photovoltaic panel and a distribution room can be timely disconnected when the box-type substation is powered off, so that a power generation system is protected and the photovoltaic substation is safer to use.

The invention will be further described with reference to the accompanying drawings in which:

referring to fig. 1 and 2, a box-type substation 100 according to a first aspect of the present invention is applied to a photovoltaic power generation system, and includes:

the photovoltaic power module 110 includes a solar cell array 111 and a junction box 112, and after the solar cell array 111 converts solar energy into direct current, the current is collected through the junction box 112.

The inverter 120 is a device for converting direct current generated by the photovoltaic module into alternating current with the same frequency and phase as those of a commercial power grid, and the inverter 120 comprises an inverter circuit 121 and a filter circuit 122, wherein the inverter circuit 121 converts the direct current introduced into the inverter 120 by the photovoltaic module 110 into alternating current, and the alternating current is subjected to waveform processing by the filter circuit 122 and then is transmitted to the distribution room 140.

The distribution room 140, the input port 144 of the distribution room 140 is connected to the output of the inverter 120 for distributing the power to the target grid 150. The distribution room 140 includes a low voltage cabinet 141, a transformer cabinet 142, and a high voltage cabinet 143, wherein the ac power transmitted from the inverter 120 is processed by the low voltage cabinet 141, boosted in the transformer cabinet 142, and finally outputted to the target grid 150 from the high voltage cabinet to match the utility grid voltage. The low-voltage cabinet 141 comprises a low-voltage incoming cabinet 1411, a low-voltage outgoing cabinet 1412, a low-voltage compensation cabinet 1413 and a communication cabinet 1414.

Referring to fig. 2 and 3, the grid-connected circuit breaker 133 is a circuit disposed between the inverter 120 and the power distribution room 140, and the grid-connected circuit breaker 133 is provided with a utility fault sensor 1331, and the utility fault sensor 1331 is connected to the target grid 150 and is configured to cause the grid-connected circuit breaker 133 to trip and trip after detecting that the target grid 150 loses power. It is understood that the grid-tie breaker 133 needs to affect the grid-tie process of the alternating current, and thus the grid-tie breaker 133 should be disposed in a circuit after the inverter 120, and additionally, the grid-tie breaker 133 should be disposed in a circuit before the distribution room 140 for the purpose of protecting the entire circuit of the distribution room 140. It is to be understood that connecting to the target grid 150 means connecting the component between the grid live line 151 and the grid neutral line 152 of the target grid.

When the photovoltaic power generation system normally operates in the box-type substation 100, the photovoltaic power supply assembly 110 converts solar energy into direct current and transmits the direct current to the inverter 120, the inverter 120 converts the direct current into alternating current and then inputs the alternating current into the grid-connected metering box, the grid-connected metering box meters the input electric energy, then current flows into the distribution room 140 from the grid-connected metering box and then is merged into the target power grid 150, and the current flows into the distribution room 140 from the inverter 120 and then passes through the grid-connected circuit breaker 133. When the target grid 150 loses power, the utility power fault inductor 1331 in the grid-connected circuit breaker 133 operates to cause the grid-connected circuit breaker 133 to trip, so that the circuit between the inverter 120 and the distribution room 140 is disconnected, and therefore, when the target grid 150 loses power, the grid-connected circuit breaker 133 trips, the inverter 120 loses load, and the photovoltaic power supply assembly 110 is separated from a closed loop, so that power generation is stopped, the safety performance of the box-type substation 100 is improved, and potential safety hazards caused by continuous power transmission of the whole box-type substation 100, which is possibly still in a continuous operation state, are eliminated.

Referring to fig. 3, according to some embodiments of the present invention, the grid-tie circuit breaker 133 selects a loss-of-mains release as the mains fault inductor 1331. The utility grid fault sensor 1331 is a device that senses a fault condition such as a voltage loss, an overcurrent, or an excessive temperature of the target grid 150 and operates to cause the grid-connected breaker 133 to trip. There are various embodiments of the mains fault sensing element 1331, and it is preferable that a mains voltage loss release is used as the mains fault sensing element 1331. The commercial power voltage-loss tripper is connected to the target power grid 150 and can play a role in under-voltage and zero-voltage protection, when the voltage of the target power grid 150 is normal, an operating handle of the commercial power voltage-loss tripper is pulled, the normally-open auxiliary contact is closed, the electromagnet is electrified, the armature is attracted by the electromagnet, a voltage-loss tripping coil of the commercial power voltage-loss tripper enables a tripping mechanism to be fastened under the condition that the target power grid 150 is electrified normally, and the grid-connected circuit breaker 133 is normally put into operation when being in a switch-on position. It is to be understood that connecting to the target grid 150 means connecting the component between the grid live line 151 and the grid neutral line 152 of the target grid. When the power failure occurs on the side of the target power grid 150 or the voltage of the target power grid 150 is too low, the voltage-loss tripping coil loses power, so that the electromagnetic force generated by the electromagnet is not enough to overcome the pulling force of the spring, the armature is pulled, and the protection action of the commercial power voltage-loss tripping device directly pushes or pushes the grid-connected circuit breaker 133 to trip through the transmission mechanism, thereby playing the role of under-voltage and zero-voltage protection. The mains voltage loss release is a preferred solution because it has simpler principles, structure and wiring than other types of mains fault sensors 1331. It should be understood that the commercial power fault sensing element 1331 operates according to the fault of the target power grid, including but not limited to the commercial power voltage-loss release in the above embodiments, the commercial power overvoltage release, the commercial power phase-loss release, and the commercial power zero-loss release, and may also be a component that operates by detecting fault conditions such as overcurrent and over-temperature of the target power grid 150, which is not described herein again.

Referring to fig. 2, according to some embodiments of the present invention, the distribution room 140 is equipped with an incoming breaker 145, specifically, the incoming breaker 145 is disposed in a transmission line inside the low-voltage incoming cabinet 1411 and connecting the low-voltage cabinet 141 and the transformation cabinet 142, the incoming breaker 145 is connected to the grid-connected breaker 133 through a safety interlock device, and the safety interlock device is used for tripping the grid-connected breaker 133 when the incoming breaker 145 performs a protection action. A safety interlock device is an automated device used for safety purposes, and the safety interlock device allows two actions to have a relationship of being restricted with each other by a mechanical mechanism or an electrical mechanism. The mechanical interlock generally uses a wire rope, a lever, or a link mechanism to change the mechanical position (or a multifunctional program lock may be used) to realize the function of the in-line breaker 145 and the grid-connected breaker 133 to perform the jump-in. In some related embodiments of the present invention, a connecting rod is used as a safety interlock device to connect the incoming line breaker 145 and the grid-connected breaker 133, and when the incoming line breaker 145 trips due to a fault in an internal circuit of the distribution room 140, the connecting rod serves as a transmission mechanism to push the grid-connected breaker 133 to trip, so as to realize the combined tripping of protection actions between the two. An electrical interlock device is a device that electrically connects a plurality of electrical components to each other to create an interlocking relationship. According to some embodiments of the invention, normally closed linkage contacts are arranged in the incoming line breaker 145 and the grid-connected breaker 133, and the protection action of the incoming line breaker 145 determines the on-off of the normally closed linkage contacts to influence the on-off of the coil of the grid-connected breaker 133, so that the interlocking relationship of the two is determined, when the incoming line breaker 145 trips, the grid-connected breaker 133 performs the linkage tripping of the protection action to cut off the circuit, and the safety performance of the box-type substation 100 is improved. It should be noted that, the mechanical interlocking device and the electrical interlocking device are used in combination, so that the reliability of the protection action jump between the grid-connected point circuit breaker and the incoming line circuit breaker 145 can be further improved. It should be understood that the joint tripping of the protection action between the point-of-presence circuit breaker and the incoming line circuit breaker 145 includes, but is not limited to, the above-mentioned embodiments. In the embodiment of the present invention, the inter-tripping grid-connected breaker 133 is arranged when the incoming line breaker 145 performs a protection action, so that the grid-connected breaker 133 and the incoming line breaker 145 can trip together when the target grid 150 fails but the internal circuit of the distribution room 140 fails, so as to further improve the safety performance of the box-type substation 100.

It should be noted that, in some embodiments of the present invention, the closing sequence of the grid-connected breaker 133 and the incoming line breaker 145 may be set in cooperation after the target power grid 150 recovers power supply. In order to ensure that the box-type substation 100 is successfully put into use after the commercial power is restored, preferably, after the commercial power is restored, the incoming line breaker 145 is switched on first, so that the power transmission line inside the distribution room 140 is in a connected state, and then the grid-connected breaker 133 is switched on, so that the box-type substation 100 can be put into use.

Referring to fig. 2, according to some embodiments of the present invention, the distribution room 140 is equipped with a safety robot 146 connected between an incoming breaker 145 and a target grid 150 for stable control of the photovoltaic power generation system during dynamic processes after grid failure. It is to be understood that connecting to the target grid 150 means connecting the component between the grid live line 151 and the grid neutral line 152 of the target grid. The safety automatic device 146 is an automatic protection device for preventing the power system from losing stability and avoiding a large-area power failure accident. In the embodiment of the invention, the distribution room 140 is provided with the safety automatic device 146, when the photovoltaic power generation system has an accident and is not operated normally, the safety automatic device 146 immediately and automatically carries out emergency treatment on the circuit of the distribution room 140 so as to prevent large-area power failure and ensure continuous power supply for important loads and normal operation of the recovery system. The types of safety robot 146 include reclosers, backup power automatic switching, low frequency load shedding and remote tripping, load shedding devices, and the like.

In some embodiments of the present invention, the substation 100 employs reclosers as the safety robots 146 of the switchyard 140. The setting mode of the automatic reclosing lock includes but is not limited to:

when a fault occurring in the target power grid 150 or the internal circuit of the distribution room 140 is temporary, after the incoming line breaker 145 trips to cut off the power supply, the automatic reclosing enables the incoming line breaker 145 to automatically reclose for a preset time, so that the distribution room 140 is prevented from being unable to recover the power consumption due to the temporary fault, and the stability of the internal circuit of the distribution room 140 is improved.

When the fault has been cleared in the target grid 150 or the circuit inside the distribution room 140, the recloser causes the incoming breaker 145 to resume power supply after a fourth time interval has elapsed since the fault was cleared. When the power supply is recovered, the target power grid 150 often accompanies the oscillation of the current, so that the target power grid 150 is unstable when the power supply is just recovered, and if the target power grid 150 is switched on at this time, a potential safety hazard is generated. Therefore, the automatic reclosing is set to be the time interval after the commercial power is recovered, so that the incoming line breaker 145 is closed, the target power grid 150 tends to be stable after the fourth time interval, and the incoming line breaker 145 is closed at the time, so that the normal work of the circuit inside the power distribution room 140 is facilitated. The setting mode of the automatic reclosing enables the safety performance of the box-type substation to be further improved.

Referring to fig. 4, according to some embodiments of the present invention, an anti-islanding protection device 123 is disposed inside the inverter 120, and the anti-islanding protection device 123 is connected to the target grid 150 and is configured to disconnect a circuit between the inverter 120 and the photovoltaic power module 110 after the target grid 150 loses power. The islanding effect is an electrical phenomenon that a certain area of a circuit has a current path and no current actually flows through, and when a power grid suddenly loses voltage, a grid-connected photovoltaic power generation system still maintains a power supply state of adjacent lines in the power grid. The anti-islanding protection device 123 is a device for preventing the islanding effect of the power grid. Referring to fig. 5, an anti-islanding protection device 123 in some embodiments of the invention includes:

and the island detection module 1231 is connected to the target grid 150 and is used for detecting whether the target grid 150 loses power. The island detection module 1231 compares the phase of the alternating current and the voltage in the circuit of the target power grid 150 with the harmonic and the normal value at any moment, and immediately sends a signal to the control module 1232 once the target power grid 150 is determined to be out of power.

The operation switch 1233 is provided in an electric circuit between the photovoltaic power module 110 and the distribution room 140, and the operation switch 1233 is used to disconnect an electric circuit for transmitting ac power from the inverter 120 to the distribution room 140 after the target grid 150 loses power. It should be understood that the arrangement of the operation switch 1233 includes, but is not limited to, that shown in the drawings.

The control module 1232 is connected to the island detection module 1231 and the operation switch 1233, and is configured to control the operation switch 1233 to be turned off after the island detection module 1231 determines that the power grid side loses power. The first time interval is the action time of the anti-islanding protection device 123, and the specific value can be flexibly set according to the use scene, because the anti-islanding protection device 123 is used for protecting the use safety of the electrical line, in a preferable scheme in the embodiment of the present invention, the first time interval is set within a time limit of not more than 2 seconds. It should be understood that the working principle of the anti-islanding protection device 123 adopted by the present invention is not limited to the above-described embodiment.

It should be noted that, in the embodiment of the present invention, the anti-islanding protection device 123 cooperates with the grid-connected circuit breaker 133 provided with the mains fault inductor 1331, when one of the components fails, the other component can still provide protection for the life safety of the circuit and the service personnel, so as to more reliably improve the safety performance of the box-type substation 100. Meanwhile, the grid-connected circuit breaker 133 is provided with obvious disconnection points, namely, manual equipment such as a knife switch and a breaking switch, so that the maintainers can judge the safety of the box-type substation 100 through the characteristic easy to recognize in the overhauling process, and convenience is brought to the operation of the maintainers.

Referring to fig. 5, according to some embodiments of the present invention, a first closing component 1234 is included, which is disposed in a circuit between the target grid 150 and the operation switch 1233, and is used to close the operation switch 1233 after a second time interval elapses after the voltage of the target grid 150 is restored. It is to be understood that connecting to the target grid 150 means connecting the component between the grid live line 151 and the grid neutral line 152 of the target grid. The first closing assembly 1234 includes, but is not limited to, the following embodiments: the islanding detection device is used for judging that the target power grid 150 is recovered to be normal and sending a signal to the control module 1232, and the control module 1232 enables the operation switch 1233 to be switched on after receiving the signal that the power grid is recovered to be normal through a second time interval. In this embodiment, the islanding detection device and the control module 1232 are used together as the first closing component 1234 to affect the operation of the operation switch 1233. A time delay relay is used, which functions to trigger an output after a second time interval upon an incoming call and then automatically disconnect the output, the output signal is directed to the switching-on coil of the operating switch 1233, and upon an incoming call to the target grid 150, the relay outputs a switching-on signal and the operating switch 1233 is automatically switched on. In this embodiment, the delay relay is used as the first closing assembly 1234 to close the operation switch 1233. The automatic closing mode is various and is not repeated herein. The second time interval is the time for the anti-islanding protection device 123 to be put into use again after the commercial power is restored, and the specific numerical value of the time interval can be flexibly set according to the use scene.

Referring to fig. 3, according to some embodiments of the present invention, a second closing assembly 134 is included, and the second closing assembly 134 is connected to a circuit between the target grid 150 and a closing coil of the grid-connected circuit breaker 133, and is used for closing the grid-connected circuit breaker 133 after a third time interval elapses after the voltage of the target grid 150 is recovered. It is to be understood that connecting to the target grid 150 means connecting the component between the grid live line 151 and the grid neutral line 152 of the target grid. The second closing assembly 134 includes, but is not limited to, the following embodiments: a time delay relay is used, which has the function that an output is triggered after a third time interval when a call comes in, then the output is automatically cut off, the output signal is led to a switching-on coil of the grid-connected circuit breaker 133, and once the target power grid 150 comes in, the relay outputs a switching-on signal, and the grid-connected circuit breaker 133 is automatically switched on. The automatic closing mode is various and is not repeated herein. The third time interval is the time for the anti-islanding protection device 123 to be put into use again after the commercial power is restored, and the specific numerical value of the third time interval can be flexibly set according to the use scene.

Referring to fig. 2 and 3, in some embodiments of the present invention, the box-type substation 100 includes a grid-connected metering cabinet 130, the grid-connected metering cabinet 130 is provided with an electric energy meter 132 and a load control device 131, the load control device 131 is connected to the inverter 120, the electric energy meter 132 is connected to the load control device 131, and a grid-connected breaker 133 is disposed between the electric energy meter 132 and the distribution room 140. The electric energy meter 132 is used for measuring and recording the generated energy, the power supply quantity, the station power consumption, the line loss power quantity and the user power consumption, and the load control device 131 is used for managing the power load and has the functions of timely pulling and closing a power supply switch of part of electric equipment in a user, providing power supply information for the user, setting and adjusting a user power consumption fixed value, alarming in an out-of-limit mode and limiting power. When the grid-connected circuit breaker 133 is arranged inside the grid-connected metering cabinet 130, the grid-connected metering cabinet 130 has the functions of metering electric energy and switching on and off of grid connection, and meanwhile, the grid-connected circuit breaker 133 is accommodated in the grid-connected metering cabinet 130, so that the arrangement space of circuits is saved, and the process of line maintenance by maintenance personnel is clearer.

According to some embodiments of the present invention, the grid-connected circuit breaker 133 may be selected from various types of circuit breakers, including but not limited to a frame circuit breaker and a molded case circuit breaker, wherein a preferred scheme is to select a dual-in dual-out molded case air switch as the grid-connected short 133. The double-in double-out switch is an air switch with the live wire and the zero wire connected into the interior of the switch. Both wires can be disconnected simultaneously in the event of a fault. The double-inlet and double-outlet type plastic shell air switch has higher safety performance compared with a common single-pole air switch.

While the preferred embodiments of the present invention have been described, the present invention is not limited to the above embodiments, and those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present invention, and such equivalent modifications or substitutions are included in the scope of the present invention defined by the claims.

Claims

1. The utility model provides a box-type substation, is applied to photovoltaic power generation system, its characterized in that includes:

a photovoltaic power module;

2. The box substation of claim 1, wherein the mains fault sensor is a mains voltage loss trip.

3. The box-type substation of claim 1, characterized in that the distribution room is equipped with an incoming line breaker, the incoming line breaker and the grid-connected breaker are connected through a safety interlock, the safety interlock is used for tripping the grid-connected breaker when the incoming line breaker takes a protective action.

4. A substation according to claim 3, wherein the distribution cubicle is equipped with safety robots connected to the incoming circuit breaker and the target grid for detecting the condition of the target grid and for providing stable control of the photovoltaic power generation system.

5. The box-type substation according to claim 1, characterized in that an anti-islanding protection device is arranged inside the inverter, and the anti-islanding protection device is connected with the target power grid and used for disconnecting a circuit between the inverter and the photovoltaic power supply assembly after the target power grid loses power.

6. The box substation of claim 5, wherein the anti-islanding protection device comprises:

7. The box substation of claim 6, comprising a first closing assembly, a circuit disposed between the target grid and the operating switch, configured to close the operating switch after a second time interval has elapsed after the target grid voltage recovers.

8. The box-type substation according to claim 1, characterized in that, includes the measurement cabinet that is incorporated into the power networks, the measurement cabinet that is incorporated into the power networks is provided with electric energy meter, burden accuse device, the burden accuse device is connected with the dc-to-ac converter, the electric energy meter is connected with the burden accuse device, the breaker that is incorporated into the power networks is provided between electric energy meter and the electricity distribution room.

9. The box substation of claim 1, wherein the grid tie circuit breaker employs a two-in, two-out molded case air switch.