Fault point position detection method in power system, and power system

Abstract

Provided in the present application are a fault point position detection method in a power system, and a power system, which are used for accurately detecting the position of a fault point when an open-circuit fault occurs in a photovoltaic system. The method comprises: for each photovoltaic unit, sending a preset instruction to the photovoltaic unit, wherein the preset instruction is used for: returning reply information to an inverter if the photovoltaic unit receives the preset instruction, and receiving the reply information by means of the inverter and a second photovoltaic unit other than a first photovoltaic unit when the first photovoltaic unit among a plurality of photovoltaic units returns the reply information to the inverter; acquiring communication quality data; and on the basis of the communication quality data, determining, from the plurality of photovoltaic units, a unit that has a communication failure. By means of the method, the position of a fault point in a photovoltaic unit where an open-circuit fault has occurred can be accurately detected, and there is no need to check the position of the fault point manually, thereby improving the troubleshooting efficiency.

Description

Fault point location detection method in power system and power system

[0001] The present application claims priority to the domestic application with the application number CN202410678513.1, the invention name of "Fault point location detection method in power system and power system", which was filed with the China Patent Office on May 28, 2024, and the whole content is incorporated herein by reference. TECHNICAL FIELD

[0002] The present application relates to the technical field of communication, in particular to a fault point location detection method in power system and power system. BACKGROUND

[0003] In a photovoltaic power station, the inverter and the photovoltaic unit usually use power line carrier communication (PLC) to communicate. The inverter is provided with a PLC master node, and each photovoltaic unit is provided with a PLC slave node. Due to the influence of factors such as device failure, magnetic ring, power line, communication distance, and surrounding interference, part of the PLC slave nodes cannot establish stable communication connection with the PLC master node, and the staff needs to manually check the fault point position, which is time-consuming and laborious, and reduces the reliability of the system.

[0004] SUMMARY

[0005] Therefore, the purpose of the present application is to provide a fault point location detection method in power system and power system to improve the reliability of the system.

[0006] In a first aspect, the embodiments of the present application provide a fault point location detection method in a power system. The method is applied to an inverter, and the inverter is in communication connection with a plurality of photovoltaic units. The method comprises: for each photovoltaic unit, sending a preset instruction to the photovoltaic unit; wherein the preset instruction is used to return reply information to the inverter if the photovoltaic unit receives the preset instruction; when a first photovoltaic unit in the plurality of photovoltaic units returns the reply information to the inverter, a second photovoltaic unit other than the first photovoltaic unit receives the reply information; the first photovoltaic unit is any one of the plurality of photovoltaic units; obtaining communication quality data; wherein the communication quality data at least includes one of the following: first quality data when the photovoltaic unit receives the preset instruction, second quality data when the photovoltaic unit receives the reply information, and third quality data when the inverter receives the reply information; and determining a communication failure unit from the plurality of photovoltaic units based on the communication quality data.

[0007] The communication quality data includes: first quality data when the photovoltaic unit receives the preset instruction; the step of obtaining the communication quality data includes: sending a first data acquisition instruction to the photovoltaic unit, so that the photovoltaic unit returns the first quality data when the photovoltaic unit receives the preset instruction; wherein the photovoltaic unit receives the preset instruction, and the first quality data corresponding to the preset instruction is detected by a preset detection method.

[0008] The communication quality data includes: second quality data when the photovoltaic unit receives the reply information; the step of obtaining the communication quality data includes: sending a second data acquisition instruction to the photovoltaic unit, so that the photovoltaic unit returns the second quality data when the photovoltaic unit receives the reply information; wherein the photovoltaic unit receives the reply information, and the second quality data corresponding to the reply information is detected by a preset detection method.

[0009] The communication quality data includes: third quality data when the inverter receives the reply information; the step of obtaining the communication quality data includes: if the inverter receives the reply information, the third quality data corresponding to the reply information is detected by a preset detection method.

[0010] After the step of obtaining the communication quality data, the method further includes: if there is a photovoltaic unit that does not return the reply information, setting the communication quality data corresponding to the photovoltaic unit that does not return the reply information as a preset data value.

[0011] The step of determining the communication fault unit from the plurality of photovoltaic units based on the communication quality data includes: taking each photovoltaic unit as a current photovoltaic unit one by one, and determining the communication fault unit from the plurality of photovoltaic units based on the second quality data when the current photovoltaic unit receives the reply information sent by the photovoltaic unit other than the current photovoltaic unit.

[0012] The step of determining the communication fault unit from the plurality of photovoltaic units based on the second quality data when the current photovoltaic unit receives the reply information sent by the photovoltaic unit other than the current photovoltaic unit includes: taking each photovoltaic unit as a current photovoltaic unit one by one, calculating the statistical parameters of the second quality data when the photovoltaic unit other than the current photovoltaic unit receives the reply information sent by the current photovoltaic unit according to a preset statistical algorithm, and determining the communication fault unit from the plurality of photovoltaic units based on the parameter value of the statistical parameter corresponding to each photovoltaic unit.

[0013] The step of determining the communication fault unit from the plurality of photovoltaic units based on the communication quality data includes: determining the communication fault unit from the plurality of photovoltaic units based on the first quality data when each photovoltaic unit receives the preset instruction.

[0014] The step of determining the communication fault unit from the plurality of photovoltaic units based on the first quality data when each photovoltaic unit receives the preset instruction comprises: determining the photovoltaic unit with the worst communication quality indicated by the first quality data as the communication fault unit.

[0015] The step of sending the preset instruction to the photovoltaic unit comprises: obtaining the equipment identification code of the photovoltaic unit, and sending the preset instruction to the photovoltaic unit in the form of unicast according to the equipment identification code.

[0016] After the step of determining the communication fault unit from the plurality of photovoltaic units based on the communication quality data, the method further comprises: determining the adjacent photovoltaic unit of the communication fault unit; determining the target adjacent photovoltaic unit with the worst communication quality when sending the reply information to the inverter from the adjacent photovoltaic units based on the communication quality data; and determining the position between the target adjacent photovoltaic unit and the communication fault unit as the communication fault position.

[0017] In a second aspect, an embodiment of the present application provides a fault point position detection method in a power system. The method is applied to a photovoltaic unit, and the photovoltaic unit is in communication connection with an inverter. The method comprises: receiving a preset instruction sent by the inverter; returning reply information to the inverter, so that the inverter obtains communication quality data after receiving the reply information returned by the photovoltaic unit; and determining a communication fault unit from a plurality of photovoltaic units based on the communication quality data. When a first photovoltaic unit in the plurality of photovoltaic units returns the reply information to the inverter, a second photovoltaic unit other than the first photovoltaic unit and the inverter receives the reply information. The first photovoltaic unit is any one of the plurality of photovoltaic units. The communication quality data at least comprises one of the following: first quality data when the photovoltaic unit receives the preset instruction, second quality data when the photovoltaic unit receives the reply information, and third quality data when the inverter receives the reply information.

[0018] After the step of receiving the preset instruction sent by the inverter, the method further comprises: recording the first quality data when the preset instruction is received; and returning the first quality data to the inverter when a first data acquisition instruction sent by the inverter is received.

[0019] The method further comprises: receiving the reply information sent by the photovoltaic unit other than the current photovoltaic unit to the inverter, and recording second quality data corresponding to the reply information sent by the photovoltaic unit other than the current photovoltaic unit to the inverter; and returning the second quality data to the inverter when a second data acquisition instruction sent by the inverter is received.

[0020] In a third aspect, the embodiments of the present application provide an electric power system, the system comprising an inverter and a plurality of photovoltaic units, the inverter being communicatively connected with the plurality of photovoltaic units; the inverter is configured to: for each photovoltaic unit, send a preset instruction to the photovoltaic unit; the photovoltaic unit is configured to: after receiving the preset instruction, return reply information to the inverter; wherein when a first photovoltaic unit of the plurality of photovoltaic units returns the reply information to the inverter, a second photovoltaic unit other than the first photovoltaic unit and the inverter receives the reply information; the first photovoltaic unit is any one of the plurality of photovoltaic units; the inverter is further configured to: acquire communication quality data; wherein the communication quality data comprises at least one of: first quality data of the photovoltaic unit when receiving the preset instruction, second quality data of the photovoltaic unit when receiving the reply information, and third quality data of the inverter when receiving the reply information; and determine a communication fault unit from the plurality of photovoltaic units based on the communication quality data.

[0021] The communication quality data comprises the first quality data of the photovoltaic unit when receiving the preset instruction; the inverter is further configured to: send a first data acquisition instruction to the photovoltaic unit, so that the photovoltaic unit returns the first quality data of the photovoltaic unit when receiving the preset instruction; wherein after the photovoltaic unit receives the preset instruction, the photovoltaic unit detects the first quality data corresponding to the preset instruction by a preset detection manner.

[0022] The communication quality data comprises the second quality data of the photovoltaic unit when receiving the reply information; the inverter is further configured to: send a second data acquisition instruction to the photovoltaic unit, so that the photovoltaic unit returns the second quality data of the photovoltaic unit when receiving the reply information; wherein after the photovoltaic unit receives the reply information, the photovoltaic unit detects the second quality data corresponding to the reply information by a preset detection manner.

[0023] The communication quality data comprises the third quality data of the inverter when receiving the reply information; the inverter is further configured to: if the inverter receives the reply information, detect the third quality data corresponding to the reply information by a preset detection manner.

[0024] The inverter is further configured to: if there is a photovoltaic unit that does not return the reply information, set the communication quality data corresponding to the photovoltaic unit that does not return the reply information as a preset data value.

[0025] The inverter is further configured to: take each photovoltaic unit as a current photovoltaic unit one by one, and determine a communication fault unit from the plurality of photovoltaic units based on the second quality data of the current photovoltaic unit when receiving the reply information sent by the photovoltaic unit other than the current photovoltaic unit.

[0026] The inverter is further configured to: take each photovoltaic unit as a current photovoltaic unit one by one, calculate statistical parameters of second quality data of the photovoltaic units other than the current photovoltaic unit when the current photovoltaic unit sends the reply information and the photovoltaic units other than the current photovoltaic unit receive the reply information according to a preset statistical algorithm; and determine the communication fault unit from the plurality of photovoltaic units based on parameter values of the statistical parameters corresponding to each photovoltaic unit.

[0027] The inverter is further configured to: determine the communication fault unit from the plurality of photovoltaic units based on the first quality data when each photovoltaic unit receives the preset instruction.

[0028] The inverter is further configured to: determine the photovoltaic unit with the worst communication quality indicated by the first quality data as the communication fault unit.

[0029] The inverter is further configured to: obtain a device identification code of the photovoltaic unit, and send the preset instruction to the photovoltaic unit in a unicast form according to the device identification code.

[0030] The inverter is further configured to: determine adjacent photovoltaic units of the communication fault unit; determine a target adjacent photovoltaic unit with the worst communication quality when sending the reply information to the inverter from the adjacent photovoltaic units based on the communication quality data; and determine a position between the target adjacent photovoltaic unit and the communication fault unit as the communication fault position.

[0031] The photovoltaic unit is further configured to: record the first quality data when receiving the preset instruction; and return the first quality data to the inverter when receiving a first data acquisition instruction sent by the inverter.

[0032] The photovoltaic unit is further configured to: receive the reply information sent by the photovoltaic units other than the current photovoltaic unit to the inverter, record second quality data corresponding to the reply information sent by the photovoltaic units other than the current photovoltaic unit to the inverter; and return the second quality data to the inverter when receiving a second data acquisition instruction sent by the inverter.

[0033] The embodiments of the present application bring the following beneficial effects:

[0034] The fault point position detection method and the power system, the inverter is in communication connection with a plurality of photovoltaic units; for each photovoltaic unit, the inverter sends a preset instruction to the photovoltaic unit, if the photovoltaic unit receives the preset instruction, returns reply information to the inverter, obtains communication quality data, and determines a communication fault unit from the plurality of photovoltaic units based on the communication quality data. Wherein, the communication quality data at least includes one of the following: the first quality data when the photovoltaic unit receives the preset instruction, the second quality data when the photovoltaic unit receives the reply information, and the third quality data when the inverter receives the reply information. Since the communication quality data can indicate the communication quality, the photovoltaic unit with the worst communication quality can be determined based on the communication quality data, so as to accurately detect the communication fault unit, without manual troubleshooting, improving the troubleshooting efficiency and improving the system reliability.

[0035] Other features and advantages of the present application will be set forth in the descriptions below, and in part will become apparent to those skilled in the art upon examination of the following or can be learned by practice of the application. The objects and other advantages of the application can be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.

[0036] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the following preferred embodiments are specifically described below, and the accompanying drawings are described in detail as follows. BRIEF DESCRIPTION OF DRAWINGS

[0037] In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the following will briefly introduce the drawings needed to be used in the specific embodiments or the prior art description. Obviously, the drawings in the following description are some embodiments of the present application, and those skilled in the art can also obtain other drawings according to these drawings without creating any creative labor.

[0038] Fig. 1 is a schematic diagram of a power system provided by an embodiment of the present application;

[0039] Fig. 2 is a flow chart of a fault point position detection method in a power system provided by an embodiment of the present application;

[0040] Fig. 3 is a communication link diagram of an inverter and a photovoltaic unit provided by an embodiment of the present application;

[0041] Fig. 4 is a flow chart of another fault point position detection method in a power system provided by an embodiment of the present application;

[0042] Fig. 5 is a communication diagram of an inverter and a plurality of photovoltaic units provided by an embodiment of the present application;

[0043] Fig. 6 is a structural schematic diagram of a power system provided by an embodiment of the present application. DETAILED DESCRIPTION

[0044] In order to make the purposes, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions of the present application will be described clearly and completely below with reference to the drawings. Obviously, the described embodiments are only some of the embodiments of the present application, but not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0045] The photovoltaic unit includes an optimizer or a shutdown device. The optimizer is a photovoltaic power optimizer, which is a DC input and DC output module level power electronics (MLPE). The photovoltaic unit also includes a photovoltaic module, which uses a predictive current and voltage technology to ensure that the module is always in an optimal working state. The photovoltaic unit can solve the problem of the influence of shadow shielding, inconsistent orientation or component electrical specification difference on power generation of a photovoltaic power station, realize maximum power output of the module, and improve system power generation.

[0046] As an example, the power system mainly includes an inverter, a photovoltaic module and an optimizer, and the photovoltaic module and the optimizer form a photovoltaic unit. The inverter includes an inverter circuit, a PLC master node CCO, an inverter control module and the like. The inverter and the photovoltaic unit communicate through a power line carrier communication mode. The PLC master node CCO included in the inverter is a master controller, and the photovoltaic unit is provided with a slave node STA of the PLC.

[0047] The PLC communication quality can be affected by a magnetic ring, a power line, a communication distance and surrounding interference, resulting in that the PLC master node CCO cannot establish a stable communication link with the slave node of some photovoltaic units. The current solution is to use PLC relay routing, and it is difficult for workers to accurately know the communication quality of each device in the system, resulting in that it is difficult to take effective measures to improve the communication quality. Even if the PLC relay routing is set, the communication between the relay site and some sites is still poor, because the relay site may have good communication quality with the PLC master node CCO, but it does not necessarily have good communication quality with the slave node of the photovoltaic unit, reducing the reliability of the communication system.

[0048] Based on the above problems, the present embodiment provides a fault point position detection method in a power system and a power system, which can be applied to power line carrier communication, for example, power line carrier communication in a photovoltaic power station or other scenarios.

[0049] For the convenience of understanding the present embodiment, first, a kind of fault point position detection method in power system disclosed in the present application is introduced in detail.The method is applied to inverter, inverter is connected with multiple photovoltaic units, for example, inverter communicates by power line carrier communication PLC;One example, the method can be applied to broken wire fault detection, as shown in Figure 2, the method includes the following steps:

[0050] Step S202, for each photovoltaic unit, send a preset instruction to photovoltaic unit;The preset instruction is used to: if photovoltaic unit receives preset instruction, return reply information to inverter;When the first photovoltaic unit in multiple photovoltaic units returns reply information to inverter, the second photovoltaic unit other than inverter and first photovoltaic unit receives reply information;First photovoltaic unit is any one of multiple photovoltaic units;

[0051] Under normal circumstances, inverter usually adopts the way of broadcast and communicates with each photovoltaic unit.The trigger condition can be set in advance, when the trigger condition is met, automatically start executing the steps of the method of the present embodiment.For example, the trigger condition can be that inverter fails to communicate with at least one photovoltaic unit, it can also be a timing condition, or manual triggering, etc.

[0052] In the above steps, inverter adopts unicast form and communicates with each photovoltaic unit.For example, inverter sends a preset instruction to photovoltaic unit 1, and then receives the reply information of photovoltaic unit 1;Then, inverter sends a preset instruction to photovoltaic unit 2, and then receives the reply information of photovoltaic unit 2;In this way, until inverter sends a preset instruction to each photovoltaic unit.

[0053] The above-mentioned preset instruction can be used to instruct photovoltaic unit to record the communication quality data corresponding to the preset instruction, and return the reply information corresponding to the preset instruction to inverter.The communication quality data can include, for example, received message signal strength RSSI, signal-to-noise ratio SNR and other data.

[0054] Step S204, obtain communication quality data, wherein the communication quality data at least includes one of the following: first quality data when photovoltaic unit receives preset instruction, second quality data when photovoltaic unit receives reply information, third quality data when inverter receives the reply information;

[0055] Step S206, based on communication quality data, determine communication failure unit from multiple photovoltaic units.

[0056] After the inverter receives the reply information, the inverter can record the signal strength RSSI, signal-to-noise ratio SNR and other data when the inverter receives the reply information as the communication quality data corresponding to the reply information, that is, the second instruction data. It should be noted that the communication quality data corresponding to the preset instruction, that is, the first instruction data, and the communication quality data corresponding to the reply information indicate communication instructions in different communication directions, wherein the communication quality data corresponding to the reply information indicates the communication quality when the inverter sends a message to the photovoltaic unit, and the communication quality data corresponding to the preset instruction indicates the communication quality when the photovoltaic unit sends a message to the inverter; at the same time, when the current photovoltaic unit sends the reply information to the inverter, the communication quality of the other photovoltaic units when receiving the reply information is the third communication quality.

[0057] At the same time, the photovoltaic unit also records the communication quality data when receiving the reply information sent by other photovoltaic units, and the communication quality data can also be sent to the inverter, that is, the aforementioned third quality data.

[0058] In actual implementation, only the communication quality data corresponding to the preset instruction can be obtained, and the communication fault unit can be determined based on the communication quality data; only the communication quality data corresponding to the reply information can be obtained, and the communication fault unit can be determined based on the communication quality data; of course, the communication fault unit can also be determined based on the communication quality data corresponding to the preset instruction and the reply information.

[0059] Specifically, based on the above communication quality data, the photovoltaic unit with the worst communication quality when receiving the preset instruction is taken as the communication fault unit, or the photovoltaic unit with the worst communication quality when receiving the reply information is taken as the communication fault unit.

[0060] The above fault point position detection method in the power system is applied to an inverter, and the inverter is in communication connection with a plurality of photovoltaic units; for each photovoltaic unit, a preset instruction is sent to the photovoltaic unit; wherein the preset instruction is used to return reply information to the inverter if the photovoltaic unit receives the preset instruction; when a first photovoltaic unit in the plurality of photovoltaic units returns the reply information to the inverter, a second photovoltaic unit other than the inverter and the first photovoltaic unit receives the reply information; the first photovoltaic unit is any one of the plurality of photovoltaic units; communication quality data is obtained; wherein the communication quality data at least includes one of the following: first quality data when the photovoltaic unit receives the preset instruction, second quality data when the photovoltaic unit receives the reply information, and third quality data when the inverter receives the reply information; based on the communication quality data, a communication fault unit is determined from the plurality of photovoltaic units. In this way, the communication fault unit can be accurately detected without manual troubleshooting, improving the troubleshooting efficiency and improving the system reliability.

[0061] The following embodiments provide various communication quality data acquisition methods.

[0062] In one way, the communication quality data includes first quality data when the photovoltaic unit receives the preset instruction; a first data acquisition instruction is sent to the photovoltaic unit to make the photovoltaic unit return the first quality data when the photovoltaic unit receives the preset instruction; wherein, after the photovoltaic unit receives the preset instruction, the first quality data corresponding to the preset instruction is detected by a preset detection method.

[0063] Since the first quality data corresponding to the preset instruction is recorded in each photovoltaic unit, after the inverter sends the preset instruction to each photovoltaic unit, the inverter can send a first data acquisition instruction to the photovoltaic unit to control the photovoltaic unit to send the first quality data corresponding to the preset instruction just recorded to the inverter. The preset detection method includes signal strength detection, signal-to-noise ratio detection, etc.

[0064] In another way, the communication quality data includes second quality data when the photovoltaic unit receives the reply information; a second data acquisition instruction is sent to the photovoltaic unit to make the photovoltaic unit return the second quality data when the photovoltaic unit receives the reply information; wherein, after the photovoltaic unit receives the reply information, the second quality data corresponding to the reply information is detected by a preset detection method.

[0065] Since the second quality data is recorded in each photovoltaic unit, after the inverter sends the preset instruction to each photovoltaic unit, the inverter can send a second data acquisition instruction to the photovoltaic unit to control the photovoltaic unit to send the second quality data corresponding to the preset instruction just recorded to the inverter. The preset detection method includes signal strength detection, signal-to-noise ratio detection, etc.

[0066] In another way, the communication quality data includes third quality data when the inverter receives the reply information; if the inverter receives the reply information, the third quality data corresponding to the reply information is detected by a preset detection method. The preset detection method includes signal strength detection, signal-to-noise ratio detection, etc.

[0067] Further, if there is a photovoltaic unit that does not return the reply information, the communication quality data corresponding to the photovoltaic unit that does not return the reply information is set to a preset data value. The preset data value may, for example, be zero or other numerical values. If the photovoltaic unit does not return the reply information, the communication between the photovoltaic unit and the inverter is interrupted, at this time, the first quality data and the second quality data in the communication quality data cannot be provided by the photovoltaic unit to the inverter, and since the photovoltaic unit does not return the reply information, the third quality data cannot be obtained by the inverter, therefore, the first quality data, the second quality data and the third quality data can all be set to the aforementioned preset data value.

[0068] In FIG. 3, three photovoltaic units are taken as an example to show the communication link between the inverter and the three photovoltaic units; for example, when the inverter sends a preset instruction to photovoltaic unit 1, photovoltaic units 2 and 3 can both receive the preset instruction, but do not reply; when photovoltaic unit 2 sends reply information to the inverter, the inverter receives the reply information, and photovoltaic unit 1 and photovoltaic unit 3 can both receive the reply information.

[0069] In one way of determining a communication failure unit, each photovoltaic unit is taken as a current photovoltaic unit one by one, and based on second quality data when the current photovoltaic unit receives reply information sent by a photovoltaic unit other than the current photovoltaic unit, a communication failure unit is determined from the plurality of photovoltaic units.

[0070] Since each photovoltaic unit sends reply information to the inverter, each photovoltaic unit also receives reply information sent by other photovoltaic units; for example, when the inverter is connected to three photovoltaic units, each photovoltaic unit can receive reply information sent by the other two, and thus two second quality data can be obtained.

[0071] Specifically, each photovoltaic unit is taken as a current photovoltaic unit one by one, and a statistical parameter of second quality data when a photovoltaic unit other than the current photovoltaic unit receives reply information sent by the current photovoltaic unit is calculated according to a preset statistical algorithm when the current photovoltaic unit sends the reply information; based on a parameter value of the statistical parameter corresponding to each photovoltaic unit, a communication failure unit is determined from the plurality of photovoltaic units.

[0072] For example, the statistical parameter can be a data sum of the second quality data, or an average value, etc. When the statistical parameter is a data sum of the second quality data, the photovoltaic unit with the lowest data sum is determined as the communication failure unit.

[0073] For example, when the inverter is connected to three photovoltaic units, photovoltaic unit A sends reply information, photovoltaic unit B can receive the reply information and record second quality data 1 of the reply information, and photovoltaic unit C can receive the reply information and record second quality data 2 of the reply information, and the data sum is the sum of the second quality data 1 and the second quality data 2.

[0074] It can be understood that the greater the value of the communication quality data, the better the corresponding communication quality.

[0075] The photovoltaic unit with the lowest data sum can be understood as the photovoltaic unit whose communication quality of the reply information received by other photovoltaic units when sending the reply information is the worst, and thus the photovoltaic unit is determined as the communication failure unit.

[0076] The following Table 1 shows an example of communication quality data.

[0077] For example, the communication quality data of the reply information received by photovoltaic unit 1 when photovoltaic unit 2 sends the reply information is 3; the communication quality data of the reply information received by photovoltaic unit 1 when photovoltaic unit 3 sends the reply information is 8.

[0078] Similarly, the communication quality data of the reply information received by photovoltaic unit 2 when photovoltaic unit 1 sends the reply information is 8; the communication quality data of the reply information received by photovoltaic unit 2 when photovoltaic unit 3 sends the reply information is 7.

[0079] The communication quality data of the reply information received by photovoltaic unit 3 when photovoltaic unit 1 sends the reply information is 7; the communication quality data of the reply information received by photovoltaic unit 3 when photovoltaic unit 2 sends the reply information is 7.

[0080] Table 1

[0081] Based on the communication quality data in Table 1, the communication quality data of the reply information received by photovoltaic unit 2 and photovoltaic unit 3 when photovoltaic unit 1 sends the reply information is 8 and 7 respectively, and the sum of the data is 15.

[0082] Similarly, the communication quality data of the reply information received by photovoltaic unit 1 and photovoltaic unit 3 when photovoltaic unit 2 sends the reply information is 3 and 2 respectively, and the sum of the data is 5.

[0083] The communication quality data of the reply information received by photovoltaic unit 1 and photovoltaic unit 2 when photovoltaic unit 3 sends the reply information is 8 and 7 respectively, and the sum of the data is 15.

[0084] Among them, the sum of the data corresponding to photovoltaic unit 2 is the lowest, so photovoltaic unit 2 is the communication fault unit.

[0085] In another way, based on the first quality data when each photovoltaic unit receives a preset instruction; determine the communication fault unit from the plurality of photovoltaic units.

[0086] The first quality data can be used to indicate the communication quality when the photovoltaic unit receives the preset instruction sent by the inverter. Specifically, the photovoltaic unit with the worst communication quality indicated by the first quality data can be determined as the communication fault unit. For example, the photovoltaic unit with the smallest first quality data is determined as the communication fault unit. The photovoltaic unit with the smallest first quality data can be understood as the photovoltaic unit with the worst communication quality when the photovoltaic unit receives the message sent by the inverter, and the photovoltaic unit is determined as the communication fault unit.

[0087] The following Table 2 gives another example of communication quality data.

[0088] Table 2

[0089] In the above Table 2, the communication quality data when the photovoltaic unit 1, the photovoltaic unit 2 and the photovoltaic unit 3 send the reply information to the inverter are 9, 2 and 7 respectively.

[0090] Similarly, the communication quality data when the inverter sends the preset instruction to the photovoltaic unit 1 is 8, and the communication quality data when the photovoltaic unit 2 and the photovoltaic unit 3 send the reply information to the inverter and the photovoltaic unit 1 receives the reply information are 9 and 8 respectively.

[0091] The communication quality data when the inverter sends the preset instruction to the photovoltaic unit 2 is 1, and the communication quality data when the photovoltaic unit 1 and the photovoltaic unit 3 send the reply information to the inverter and the photovoltaic unit 2 receives the reply information are 8 and 7 respectively.

[0092] The communication quality data when the inverter sends the preset instruction to the photovoltaic unit 3 is 7, and the communication quality data when the photovoltaic unit 1 and the photovoltaic unit 2 send the reply information to the inverter and the photovoltaic unit 3 receives the reply information are 7 and 8 respectively.

[0093] Based on the communication quality data in Table 2, the first quality data when each photovoltaic unit receives the preset instruction are 8, 1 and 7 respectively, wherein the minimum is the photovoltaic unit 2, and therefore the photovoltaic unit 2 is the communication fault unit.

[0094] In a specific implementation, the device identification code of the photovoltaic unit is acquired, and the preset instruction is sent to the photovoltaic unit in the form of unicast according to the device identification code.

[0095] In the communication system, the photovoltaic unit is preset with a unique device identification code, and the photovoltaic unit corresponds to the device identification code one by one. For example, when the inverter sends the preset instruction to the photovoltaic unit 1, the device identification code of the photovoltaic unit 1 can be carried in the preset instruction, so that the photovoltaic unit 1 can receive the preset instruction. The device identification code can be an SN code, a device address or other forms of identification code.

[0096] After the communication fault unit is determined, the staff can carry out targeted maintenance, so as to exclude the fault and restore the normal communication between the photovoltaic unit and the inverter.

[0097] In actual implementation, the adjacent photovoltaic unit of the communication fault unit is determined; based on the communication quality data, the target adjacent photovoltaic unit with the worst communication quality when sending the reply information to the inverter is determined from the adjacent photovoltaic units; and the position between the target adjacent photovoltaic unit and the communication fault unit is determined as the fault point position.

[0098] Taking Table 2 above as an example, the photovoltaic unit 2 is a communication fault unit. The photovoltaic unit 1 and the photovoltaic unit 3 are adjacent photovoltaic units of the photovoltaic unit 2, wherein the communication quality data of the photovoltaic unit 1 when sending the reply information to the inverter is 9, the communication quality data of the photovoltaic unit 3 when sending the reply information to the inverter is 7, and the communication quality data of the photovoltaic unit 3 is the lowest. It can be known that the fault point position is located between the photovoltaic unit 2 and the photovoltaic unit 3. The fault point position may have a fault such as disconnection, virtual connection, electric arc, etc.

[0099] The fault point position causes the signal strength of the direction in which the photovoltaic unit sends the message to the inverter to attenuate. By comparing the communication quality data, such as the signal strength value, of the message received by the inverter from each photovoltaic unit, it can be known that the signal strength value of the photovoltaic unit near the fault point position is lower than that of other photovoltaic units. Based on this, the communication fault unit and the fault point position can be determined.

[0100] Referring to another fault point position detection method in a power system shown in FIG. 4, the method is applied to a photovoltaic unit, and the photovoltaic unit communicates with an inverter through PLC; the method comprises the following steps:

[0101] Step S402, receiving a preset instruction sent by the inverter;

[0102] Step S404, returning reply information to the inverter, so that the inverter receives the reply information returned by the photovoltaic unit, obtains communication quality data corresponding to the preset instruction and / or the reply information, and determines a communication fault unit from a plurality of photovoltaic units based on the communication quality data.

[0103] Among them, when the first photovoltaic unit in the plurality of photovoltaic units returns the reply information to the inverter, the inverter and the second photovoltaic unit other than the first photovoltaic unit receive the reply information; the first photovoltaic unit is any one of the plurality of photovoltaic units; the communication quality data at least includes one of the following: first quality data when the photovoltaic unit receives the preset instruction, second quality data when the photovoltaic unit receives the reply information, and third quality data when the inverter receives the reply information.

[0104] The fault point position detection method in the power system is applied to a photovoltaic unit, the photovoltaic unit communicates with an inverter through PLC; a preset instruction sent by the inverter is received; reply information is returned to the inverter, so that after the inverter receives the reply information returned by the photovoltaic unit, communication quality data corresponding to the preset instruction and / or the reply information is acquired, and a communication fault unit is determined from the plurality of photovoltaic units based on the communication quality data; wherein when the first photovoltaic unit in the plurality of photovoltaic units returns the reply information to the inverter, the inverter and a second photovoltaic unit other than the first photovoltaic unit receive the reply information. In this way, the communication fault unit can be accurately detected without manual troubleshooting, improving the troubleshooting efficiency and improving the system reliability.

[0105] Further, after the photovoltaic unit receives the preset instruction sent by the inverter, first quality data corresponding to the received preset instruction is recorded, and when a first data acquisition instruction sent by the inverter is received, the first quality data is returned to the inverter.

[0106] In addition, the photovoltaic unit can provide the above-mentioned first quality data to the inverter after receiving the first data acquisition instruction sent by the inverter, or actively provide the above-mentioned first quality data to the inverter.

[0107] Further, the reply information sent by the photovoltaic unit other than the current photovoltaic unit to the inverter is received, and second quality data corresponding to the reply information sent by the photovoltaic unit other than the current photovoltaic unit to the inverter is recorded; when a second data acquisition instruction sent by the inverter is received, the second quality data is returned to the inverter.

[0108] In addition, the photovoltaic unit can provide the above-mentioned second quality data to the inverter after receiving the second data acquisition instruction sent by the inverter, or actively provide the above-mentioned second quality data to the inverter.

[0109] Referring to the communication schematic diagram of the inverter and the plurality of photovoltaic units shown in FIG. 5. In this embodiment, three photovoltaic units are taken as an example for description. The three photovoltaic units are photovoltaic unit 1, photovoltaic unit 2 and photovoltaic unit 3.

[0110] Step S501, the inverter sends a preset instruction 1 to the photovoltaic unit 1;

[0111] Step S502, the photovoltaic unit 1 records the communication quality data corresponding to the preset instruction 1, and sends reply information 1 to the inverter;

[0112] Step S503, the inverter receives the reply information 1, and records the communication quality data corresponding to the reply information 1;

[0113] Step S504, the photovoltaic unit 2 receives the reply information 1, and records the communication quality data corresponding to the reply information 1;

[0114] Step S505, the photovoltaic unit 3 receives the reply information 1, and records the communication quality data corresponding to the reply information 1;

[0115] Step S506, the inverter sends a preset instruction 2 to the photovoltaic unit 2;

[0116] Step S507, the photovoltaic unit 2 records the communication quality data corresponding to the preset instruction 2, and sends the reply information 2 to the inverter;

[0117] Step S508, the inverter receives the reply information 2, and records the communication quality data corresponding to the reply information 2;

[0118] Step S509, the photovoltaic unit 1 receives the reply information 2, and records the communication quality data corresponding to the reply information 2;

[0119] Step S510, the photovoltaic unit 3 receives the reply information 2, and records the communication quality data corresponding to the reply information 2;

[0120] Step S511, the inverter sends a preset instruction 3 to the photovoltaic unit 3;

[0121] Step S512, the photovoltaic unit 3 records the communication quality data corresponding to the preset instruction 3, and sends the reply information 3 to the inverter;

[0122] Step S513, the inverter receives the reply information 3, and records the communication quality data corresponding to the reply information 3;

[0123] Step S514, the photovoltaic unit 2 receives the reply information 3, and records the communication quality data corresponding to the reply information 3;

[0124] Step S515, the photovoltaic unit 1 receives the reply information 3, and records the communication quality data corresponding to the reply information 3;

[0125] Step S516, the inverter sends a data acquisition instruction to the photovoltaic unit 1, the photovoltaic unit 2 and the photovoltaic unit 3;

[0126] Step S517, the photovoltaic unit 1, the photovoltaic unit 2 and the photovoltaic unit 3 send the communication quality data to the inverter;

[0127] Step S518, the inverter determines the communication fault unit according to the communication quality data.

[0128] Corresponding to the above method embodiment, the present embodiment also provides a power system, as shown in Figure 6, which comprises an inverter and a plurality of photovoltaic units, the inverter being in communication connection with the plurality of photovoltaic units; N photovoltaic units are shown in Figure 6, the N photovoltaic units being connected with the inverter through a communication bus, and the N photovoltaic units can also communicate with each other through the communication bus. The communication bus can be a PLC bus or other communication bus.

[0129] The above inverter is configured to: for each photovoltaic unit, send a preset instruction to the photovoltaic unit;

[0130] The above photovoltaic unit is configured to: after receiving the preset instruction, return reply information to the inverter; wherein when a first photovoltaic unit in the plurality of photovoltaic units returns the reply information to the inverter, a second photovoltaic unit other than the inverter and the first photovoltaic unit receives the reply information; the first photovoltaic unit is any one of the plurality of photovoltaic units.

[0131] The above inverter is further configured to: obtain communication quality data; wherein the communication quality data at least includes one of the following: first quality data when the photovoltaic unit receives the preset instruction, second quality data when the photovoltaic unit receives the reply information, and third quality data when the inverter receives the reply information; based on the communication quality data, determine a communication fault unit from the plurality of photovoltaic units.

[0132] The above communication quality data includes: first quality data when the photovoltaic unit receives the preset instruction; the above inverter is further configured to: send a first data acquisition instruction to the photovoltaic unit, so that the photovoltaic unit returns the first quality data when the photovoltaic unit receives the preset instruction; wherein after the photovoltaic unit receives the preset instruction, the first quality data corresponding to the preset instruction is detected by a preset detection method.

[0133] The above communication quality data includes: second quality data when the photovoltaic unit receives the reply information; the above inverter is further configured to: send a second data acquisition instruction to the photovoltaic unit, so that the photovoltaic unit returns the second quality data when the photovoltaic unit receives the reply information; wherein after the photovoltaic unit receives the reply information, the second quality data corresponding to the reply information is detected by a preset detection method.

[0134] The above communication quality data includes: third quality data when the inverter receives the reply information; the above inverter is further configured to: if the inverter receives the reply information, the third quality data corresponding to the reply information is detected by a preset detection method.

[0135] The above inverter is further configured to: if there is a photovoltaic unit that has not returned the reply information, set the communication quality data corresponding to the photovoltaic unit that has not returned the reply information to a preset data value.

[0136] The inverter is further configured to: take each photovoltaic unit as a current photovoltaic unit one by one, determine a communication fault unit from the plurality of photovoltaic units based on second quality data of the current photovoltaic unit when the current photovoltaic unit receives reply information sent by other photovoltaic units than the current photovoltaic unit.

[0137] The inverter is further configured to: take each photovoltaic unit as a current photovoltaic unit one by one, calculate a statistical parameter of the second quality data of other photovoltaic units than the current photovoltaic unit when the current photovoltaic unit sends reply information and the current photovoltaic unit receives the reply information according to a preset statistical algorithm; and determine a communication fault unit from the plurality of photovoltaic units based on a parameter value of the statistical parameter corresponding to each photovoltaic unit.

[0138] The inverter is further configured to: determine a communication fault unit from the plurality of photovoltaic units based on first quality data when each photovoltaic unit receives a preset instruction.

[0139] The inverter is further configured to: determine a photovoltaic unit with the worst communication quality indicated by the first quality data as the communication fault unit.

[0140] The inverter is further configured to: obtain a device identification code of the photovoltaic unit, and send the preset instruction to the photovoltaic unit in a unicast form according to the device identification code.

[0141] The inverter is further configured to: determine a neighboring photovoltaic unit of the communication fault unit, determine a target neighboring photovoltaic unit with the worst communication quality when sending reply information to the inverter from the neighboring photovoltaic units based on communication quality data, and determine a communication fault position as a position between the target neighboring photovoltaic unit and the communication fault unit.

[0142] The photovoltaic unit is further configured to: record the first quality data when receiving the preset instruction, and return the first quality data to the inverter when receiving a first data acquisition instruction sent by the inverter.

[0143] The photovoltaic unit is further configured to: receive reply information sent by other photovoltaic units than the current photovoltaic unit to the inverter, record second quality data corresponding to the reply information sent by other photovoltaic units than the current photovoltaic unit to the inverter, and return the second quality data to the inverter when receiving a second data acquisition instruction sent by the inverter.

[0144] The fault point position detection method and the power system have low cost and high efficiency, do not need additional devices and special signal processing, and can detect faults only based on normal message signals sent by the system. The channel link quality of the current string can be analyzed through the link quality between stations, and a suitable relay point can be selected to ensure normal communication.

[0145] Furthermore, in the description of the embodiments of this application, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0146] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0147] In the description of this application, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0148] Finally, it should be noted that the above embodiments are merely specific implementations of this application, used to illustrate the technical solutions of this application, and not to limit them. The protection scope of this application is not limited thereto. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can still modify or easily conceive of changes to the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some of the technical features, within the technical scope disclosed in this application. Such modifications, changes, or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be covered within the protection scope of this application. Therefore, the protection scope of this application should be determined by the protection scope of the claims.

Claims

1. A method of fault point location in an electric power system, characterized by, The method is applied to an inverter, which is in communication connection with a plurality of photovoltaic units; the fault point position detection method in the power system comprises: For each photovoltaic unit, a preset instruction is sent to the photovoltaic unit; wherein the preset instruction is used to return reply information to the inverter if the photovoltaic unit receives the preset instruction; when a first photovoltaic unit in the plurality of photovoltaic units returns the reply information to the inverter, a second photovoltaic unit other than the first photovoltaic unit and the inverter receives the reply information; the first photovoltaic unit is any one of the plurality of photovoltaic units; Communication quality data is acquired; wherein the communication quality data at least includes one of the following: first quality data when the photovoltaic unit receives the preset instruction, second quality data when the photovoltaic unit receives the reply information, and third quality data when the inverter receives the reply information; Based on the communication quality data, a communication failure unit is determined from the plurality of photovoltaic units.

2. The fault point location method in a power system according to claim 1, characterized by, The communication quality data includes the first quality data when the photovoltaic unit receives the preset instruction; The step of acquiring the communication quality data comprises: A first data acquisition instruction is sent to the photovoltaic unit, so that the photovoltaic unit returns the first quality data when the photovoltaic unit receives the preset instruction; wherein after the photovoltaic unit receives the preset instruction, the first quality data corresponding to the preset instruction is detected by a preset detection method.

3. The fault point location method in a power system according to claim 1, characterized by, The communication quality data includes the second quality data when the photovoltaic unit receives the reply information; The step of acquiring the communication quality data comprises: A second data acquisition instruction is sent to the photovoltaic unit, so that the photovoltaic unit returns the second quality data when the photovoltaic unit receives the reply information; wherein after the photovoltaic unit receives the reply information, the second quality data corresponding to the reply information is detected by a preset detection method. The communication quality data includes the third quality data when the inverter receives the reply information; 4. The fault point location method in a power system according to claim 1, characterized by, The step of acquiring the communication quality data comprises: If the inverter receives the reply information, the third quality data corresponding to the reply information is detected by a preset detection method. After the step of acquiring the communication quality data, the fault point position detection method in the power system further comprises:

5. The fault point location method in a power system according to claim 1, characterized by, If there is a photovoltaic unit that does not return the reply information, the communication quality data corresponding to the photovoltaic unit that does not return the reply information is set as a preset data value. The step of determining the communication failure unit from the plurality of photovoltaic units based on the communication quality data comprises:

6. The fault point location method in a power system according to claim 1, wherein, Each photovoltaic unit is taken as a current photovoltaic unit one by one, and based on the second quality data when the current photovoltaic unit receives the reply information sent by the photovoltaic unit other than the current photovoltaic unit, the communication failure unit is determined from the plurality of photovoltaic units. ​ 7. The fault point location method in a power system according to claim 6, characterized by, The step of determining the communication fault unit from the plurality of photovoltaic units based on the second quality data of the reply information received by the photovoltaic units other than the current photovoltaic unit when the current photovoltaic unit sends the reply information, comprises: According to a preset statistical algorithm, the statistical parameters of the second quality data of the reply information received by the photovoltaic units other than the current photovoltaic unit when the current photovoltaic unit sends the reply information are calculated one by one for each photovoltaic unit as the current photovoltaic unit; The communication fault unit is determined from the plurality of photovoltaic units based on the parameter value of the statistical parameter corresponding to each photovoltaic unit.

8. The fault point location method in a power system according to claim 1, characterized by, The step of determining the communication fault unit from the plurality of photovoltaic units based on the communication quality data, comprises: The communication fault unit is determined from the plurality of photovoltaic units based on the first quality data of the preset instruction received by each photovoltaic unit.

9. The fault point location method in a power system according to claim 8, characterized by, The step of determining the communication fault unit from the plurality of photovoltaic units based on the first quality data of the preset instruction received by each photovoltaic unit, comprises: The photovoltaic unit with the worst communication quality indicated by the first quality data is determined as the communication fault unit.

10. The fault point location method in a power system according to claim 1, characterized by, The step of sending a preset instruction to the photovoltaic unit, comprises: The device identification code of the photovoltaic unit is obtained, and the preset instruction is sent to the photovoltaic unit in the form of unicast according to the device identification code.

11. The fault point location method in a power system according to claim 1, characterized by, After the step of determining the communication fault unit from the plurality of photovoltaic units based on the communication quality data, the fault point position detection method in the power system further comprises: The adjacent photovoltaic unit of the communication fault unit is determined; The target adjacent photovoltaic unit with the worst communication quality when sending the reply information to the inverter is determined from the adjacent photovoltaic units based on the communication quality data; The position between the target adjacent photovoltaic unit and the communication fault unit is determined as the communication fault position.

12. A method of fault point location in an electric power system, characterized by, The method is applied to a photovoltaic unit, and the photovoltaic unit is in communication connection with an inverter; the fault point position detection method in the power system comprises: Receiving a preset instruction sent by the inverter; Returning a reply information to the inverter, so that the inverter obtains communication quality data after receiving the reply information returned by the photovoltaic unit; and determining a communication fault unit from a plurality of photovoltaic units based on the communication quality data; The first photovoltaic unit in the plurality of photovoltaic units returns the reply information to the inverter, and the inverter and a second photovoltaic unit other than the first photovoltaic unit receive the reply information; the first photovoltaic unit is any one of the plurality of photovoltaic units; the communication quality data at least includes one of the following: the first quality data of the photovoltaic unit receiving the preset instruction, the second quality data of the photovoltaic unit receiving the reply information, and the third quality data of the inverter receiving the reply information.

13. The fault point location method in a power system according to claim 12, wherein, After the step of receiving the preset instruction sent by the inverter, the method further comprises: recording the first quality data when the preset instruction is received; When the first data acquisition instruction sent by the inverter is received, the first quality data is returned to the inverter.

14. The fault location detection method in a power system according to claim 12, characterized in that, The fault point position detection method of the power system further comprises: receiving reply information sent by the photovoltaic unit other than the current photovoltaic unit to the inverter, recording second quality data corresponding to the reply information sent by the photovoltaic unit other than the current photovoltaic unit to the inverter; when the second data acquisition instruction sent by the inverter is received, returning the second quality data to the inverter.

15. A power system characterized by, The system comprises an inverter and a plurality of photovoltaic units, and the inverter is in communication connection with the plurality of photovoltaic units; The inverter is configured to: for each photovoltaic unit, send a preset instruction to the photovoltaic unit; The photovoltaic unit is configured to: after receiving the preset instruction, return reply information to the inverter; wherein when the first photovoltaic unit in the plurality of photovoltaic units returns the reply information to the inverter, the inverter and the second photovoltaic unit other than the first photovoltaic unit receive the reply information; the first photovoltaic unit is any one of the plurality of photovoltaic units; The inverter is further configured to: acquire communication quality data; wherein the communication quality data comprises at least one of the following: first quality data when the photovoltaic unit receives the preset instruction, second quality data when the photovoltaic unit receives the reply information, and third quality data when the inverter receives the reply information; and determine a communication fault unit from the plurality of photovoltaic units based on the communication quality data. The communication quality data comprises: first quality data when the photovoltaic unit receives the preset instruction; 16. The power system of claim 15, wherein, The inverter is further configured to: send a first data acquisition instruction to the photovoltaic unit, so that the photovoltaic unit returns the first quality data when the photovoltaic unit receives the preset instruction; wherein after the photovoltaic unit receives the preset instruction, the first quality data corresponding to the preset instruction is detected by a preset detection method. The communication quality data comprises: second quality data when the photovoltaic unit receives the reply information; 17. The power system of claim 15, wherein, The inverter is further configured to: send a second data acquisition instruction to the photovoltaic unit, so that the photovoltaic unit returns the second quality data when the photovoltaic unit receives the reply information; wherein after the photovoltaic unit receives the reply information, the second quality data corresponding to the reply information is detected by a preset detection method. The communication quality data comprises: third quality data when the inverter receives the reply information; 18. The power system of claim 15, wherein, The inverter is further configured to: if the inverter receives the reply information, the third quality data corresponding to the reply information is detected by a preset detection method. The inverter is further configured to:

19. The power system of claim 15, wherein, if there is a photovoltaic unit that does not return the reply information, set the communication quality data corresponding to the photovoltaic unit that does not return the reply information to a preset data value. The inverter is further configured to:

20. The power system of claim 15, wherein, determine a communication fault unit from the plurality of photovoltaic units based on second quality data when each photovoltaic unit is taken as a current photovoltaic unit and the current photovoltaic unit receives the reply information sent by the photovoltaic unit other than the current photovoltaic unit. The inverter is further configured to:

21. The power system according to claim 20, characterized in that, ​ The first quality data of each photovoltaic unit is recorded when the photovoltaic unit receives the preset instruction. The communication fault unit is determined from the plurality of photovoltaic units based on the parameter value of the statistical parameter corresponding to each photovoltaic unit.

22. The power system of claim 15, wherein, The inverter is further configured to: The communication fault unit is determined from the plurality of photovoltaic units based on the first quality data of each photovoltaic unit receiving the preset instruction.

23. The power system of claim 22, wherein, The inverter is further configured to: The photovoltaic unit with the worst communication quality indicated by the first quality data is determined as the communication fault unit.

24. The power system of claim 15, wherein, The inverter is further configured to: The equipment identification code of the photovoltaic unit is obtained, and the preset instruction is sent to the photovoltaic unit in unicast form according to the equipment identification code.

25. The power system of claim 15, wherein, The inverter is further configured to: The adjacent photovoltaic unit of the communication fault unit is determined. The target adjacent photovoltaic unit with the worst communication quality when sending the reply information to the inverter is determined from the adjacent photovoltaic units based on the communication quality data. The position between the target adjacent photovoltaic unit and the communication fault unit is determined as the communication fault position.

26. The power system of claim 15, wherein, The photovoltaic unit is further configured to: The first quality data of receiving the preset instruction is recorded. When the first data acquisition instruction sent by the inverter is received, the first quality data is returned to the inverter.

27. The power system of claim 15, wherein, The photovoltaic unit is further configured to: The reply information sent by the photovoltaic unit other than the current photovoltaic unit to the inverter is received, and the second quality data corresponding to the reply information sent by the photovoltaic unit other than the current photovoltaic unit to the inverter is recorded. When the second data acquisition instruction sent by the inverter is received, the second quality data is returned to the inverter.

28. An inverter, comprising: A method for detecting the fault position in the power system as claimed in any one of claims 1-14 is provided.

Images