阅读说明：本技术 一种光伏系统及抑制电势衰减和绝缘监控的方法 (Photovoltaic system and method for inhibiting potential attenuation and monitoring insulation ) 是由 唐牧 张彤 于 2019-09-25 设计创作，主要内容包括：本发明公开了一种光伏系统及抑制电势衰减和绝缘监控的方法,所述抑制电势诱导衰减效应系统包括光伏并网逆变器,所述光伏并网逆变器外安装有若干结构相同的光伏板,所述光伏板与光伏并网逆变器电性相连,所述光伏板与光伏并网逆变器之间安装有电势诱导衰减修复控制装置,所述电势诱导衰减修复控制装置分别与所述光伏并网逆变器和所述光伏板电性相连。本发明的有益效果是,可以抑制优化光伏电站发电效率差异性,电池组件性能衰减现象；对光伏电站直流系统绝缘监测,更好地保证设备的安全可靠运行,减少光伏电站设备的故障时间,有效提升业主的经济效益；智能远程监控功能,实时在线掌握每台设备的运行数据和运营情况。(The invention discloses a photovoltaic system and a method for inhibiting potential attenuation and monitoring insulation, wherein the system for inhibiting potential induced attenuation effect comprises a photovoltaic grid-connected inverter, a plurality of photovoltaic panels with the same structure are installed outside the photovoltaic grid-connected inverter, the photovoltaic panels are electrically connected with the photovoltaic grid-connected inverter, a potential induced attenuation repair control device is installed between the photovoltaic panels and the photovoltaic grid-connected inverter, and the potential induced attenuation repair control device is respectively electrically connected with the photovoltaic grid-connected inverter and the photovoltaic panels. The invention has the advantages that the phenomena of poor power generation efficiency and battery component performance attenuation of the optimized photovoltaic power station can be inhibited; the photovoltaic power station direct current system is subjected to insulation monitoring, so that safe and reliable operation of equipment is better guaranteed, the fault time of the photovoltaic power station equipment is reduced, and the economic benefit of an owner is effectively improved; the intelligent remote monitoring function is used for mastering the operation data and the operation condition of each device on line in real time.)

1. The utility model provides a photovoltaic system, its characterized in that, suppression electric potential induced attenuation effect system includes photovoltaic grid-connected inverter, photovoltaic grid-connected inverter installs the same photovoltaic board of a plurality of structures outward, photovoltaic board and photovoltaic grid-connected inverter electrical property link to each other, install electric potential induced attenuation restoration controlling means between photovoltaic board and the photovoltaic grid-connected inverter, electric potential induced attenuation restoration controlling means respectively with photovoltaic grid-connected inverter with photovoltaic board electrical property links to each other.

2. The photovoltaic system of claim 1, further comprising: the cabinet converges, the cabinet that converges is installed outward to the photovoltaic grid-connected inverter, the cabinet that converges links to each other with the photovoltaic grid-connected inverter electrical property, converge the cabinet and install the same photovoltaic board of a plurality of structures outward, the photovoltaic board with converge and install the same current sensor of a plurality of structures between the cabinet, current sensor respectively with the photovoltaic board with it links to each other to converge the cabinet electrical property, converge the cabinet and install insulating detection device outward, theater detection device respectively with current sensor converge the case with the photovoltaic grid-connected inverter electrical property links to each other.

3. A method for suppressing potential decay of a photovoltaic system is applied to the photovoltaic system in claim 1, and comprises the following specific steps:

a. a processor is adopted, and software and hardware are combined to form a PID repair control device with virtual resistance potential control;

b. b, adding a self-adaptive series virtual resistance voltage source between the negative electrode of the photovoltaic system and the ground by using the PID repair control device in the step a;

c. daytime mode was used when on the daytime and nighttime mode was used when on the night, the daytime state was analyzed.

4. The method for suppressing potential decay of a photovoltaic system according to claim 3, wherein the daytime mode in the step c comprises the following specific steps:

s1.1, using the PID repair control device to raise the low potential to the ground and serially connecting a high virtual resistor;

and s1.2, inhibiting loss of positive ions of the back plate of the assembly and inhibiting attenuation of PID.

5. The method for suppressing potential decay of a photovoltaic system according to claim 3, wherein the night mode in the step c comprises the following specific steps:

s2.1, using the PID repair control device to perform high-voltage low-resistance PID recovery on all components of the system;

and s2.2, inhibiting the loss of negative ions of the back plate of the assembly and inhibiting the attenuation of PID.

6. The method for suppressing potential decay of a photovoltaic system according to claim 2, wherein the processor in step a is a high-performance 32-bit digital DSP processor.

7. An insulation monitoring method of a photovoltaic system, wherein the insulation monitoring method of the photovoltaic system is applied to the photovoltaic system in claim 2, and comprises the following specific steps:

a. adopting a balanced and unbalanced bridge compatible detection mode to monitor the voltages to earth of the positive bus and the negative bus in real time in an isolated manner;

b. calculating the insulation resistance value of the bus by a direct-current voltage detection method;

c. when the bus insulation is lowered to a set value, starting branch inspection;

d. a branch power resistor RK is put into the bus, and the current of the current sensor is read through an RS485 bus;

e. collecting the voltage of a bus line to ground and the current value collected by each branch current sensor;

f. calculating the positive and negative grounding impedances of the branch by a branch leakage current detection method according to the data collected in the step e, and finishing the calculation of the positive and negative grounding resistances of each branch;

g. monitoring the condition that the positive and negative ends of the bus are reduced in resistance to the ground by using a resistor switching method;

h. and transmitting the collected resistance data into the switch, transmitting the resistance data to the background server, and monitoring and managing through background central centralized control.

Technical Field

The invention relates to the field of photovoltaic power stations, in particular to a photovoltaic system and a method for inhibiting potential attenuation and monitoring insulation.

Background

With the continuous development of the photovoltaic industry, the difference of the application environments of the photovoltaic power stations causes the difference of the power generation efficiency of the photovoltaic power stations. Since 2012, a quality problem related to components is largely exposed in photovoltaic power stations, and the PID effect has received wide attention from the industry as one of important factors affecting power generation of power stations. The PID (Potential induced degradation) effect is a phenomenon that the performance of the battery assembly is degraded due to ion migration under the action of high voltage between the battery piece and the grounded metal frame, which is caused by the packaging material of the battery assembly and the materials of the upper surface and the lower surface of the battery assembly. The PID can affect the power generation capacity and the total output power of the whole system, seriously affects the investment yield of the photovoltaic power station, is a terrorist killer of the generated energy of the photovoltaic power station, and becomes one of industry pain points for the quality of the complaint components of buyers in recent years.

Meanwhile, the photovoltaic power station direct current system is complex in wiring, multiple in branches and long in distance, and line insulation faults can occur inevitably. In annual electrical system faults, ground faults account for 90% to 95% of electrical system faults. The ground fault of the photovoltaic power station direct current system can not only cause the faults of power short circuit, fuse fusing, switch burning and the like, and the safe operation of the equipment in the station is influenced, so that the service efficiency of the equipment in the station is reduced, the time of fault shutdown is increased, the loss of generated energy of an owner is reduced, and the personal safety of operation and maintenance personnel can be threatened.

Modern information technologies such as internet, cloud computing, big data, artificial intelligence, IoT communication and the like are deeply fused with the photovoltaic industry in the future; the photovoltaic power station will develop towards the direction of digitization, intellectuality, informationization at a high speed, and wisdom photovoltaic power station will become the mainstream promptly.

The photovoltaic power station can generate a PID effect due to the influence of environmental factors such as solarization, humidity and large temperature difference. The direct damage of the PID effect is that a large amount of charges are accumulated on the surface of the photovoltaic cell plate, so that the surface of the cell is passivated, the filling factor is reduced, the power generation power of the photovoltaic power station is further rapidly attenuated, and the economic benefit of the photovoltaic power station is linearly reduced.

As the commissioning time of photovoltaic power plants accumulates, the related technical requirements have not met the latest power technology standards. The original insulation monitoring device does not have the monitoring and displaying functions of bus voltage and positive and negative voltage to ground, and simultaneously lacks the alarm functions of abnormal bus voltage, deviation of the bus voltage to ground and the like. When each branch of the direct current system has an insulation fault, the original system cannot effectively early warn and monitor faults such as insulation reduction, alternating current channeling, direct current channeling and the like of each branch, cannot accurately and timely judge the fault position and reason, and is not beneficial to field analysis and fault troubleshooting.

At present, the characteristics of the large-scale photovoltaic power station in China are that the occupied area is large, the types of components and inverters are numerous, the standards are different, the product quality is different, the starting and stopping of the photovoltaic equipment are different from that of wind power and hydropower, and more operation and maintenance personnel are needed. Therefore, rapid information processing and fault analysis of photovoltaic power plants are more important.

Disclosure of Invention

The invention aims to solve the problems and designs a photovoltaic system and a method for restraining potential attenuation and monitoring insulation.

The technical scheme of the invention is that the system for inhibiting the potential induced attenuation effect comprises a photovoltaic grid-connected inverter, a plurality of photovoltaic panels with the same structure are installed outside the photovoltaic grid-connected inverter, the photovoltaic panels are electrically connected with the photovoltaic grid-connected inverter, a potential induced attenuation repair control device is installed between the photovoltaic panels and the photovoltaic grid-connected inverter, and the potential induced attenuation repair control device is respectively electrically connected with the photovoltaic grid-connected inverter and the photovoltaic panels.

Preferably, the photovoltaic system further comprises: the cabinet converges, the cabinet that converges is installed outward to the photovoltaic grid-connected inverter, the cabinet that converges links to each other with the photovoltaic grid-connected inverter electrical property, converge the cabinet and install the same photovoltaic board of a plurality of structures outward, the photovoltaic board with converge and install the same current sensor of a plurality of structures between the cabinet, current sensor respectively with the photovoltaic board with it links to each other to converge the cabinet electrical property, converge the cabinet and install insulating detection device outward, theater detection device respectively with current sensor converge the case with the photovoltaic grid-connected inverter electrical property links to each other.

Preferably, the method for suppressing potential decay of the photovoltaic system is applied to the photovoltaic system in claim 1, and comprises the following specific steps:

a. a processor is adopted, and software and hardware are combined to form a PID repair control device with virtual resistance potential control;

b. b, adding a self-adaptive series virtual resistance voltage source between the negative electrode of the photovoltaic system and the ground by using the PID repair control device in the step a;

c. daytime mode was used when on the daytime and nighttime mode was used when on the night, the daytime state was analyzed.

Preferably, the daytime mode in step c includes the following specific steps:

s1.1, using the PID repair control device to raise the low potential to the ground and serially connecting a high virtual resistor;

and s1.2, inhibiting loss of positive ions of the back plate of the assembly and inhibiting attenuation of PID.

Preferably, the night mode in step c includes the following specific steps:

s2.1, using the PID repair control device to perform high-voltage low-resistance PID recovery on all components of the system;

and s2.2, inhibiting the loss of negative ions of the back plate of the assembly and inhibiting the attenuation of PID.

Preferably, the processor in the step a is a high-performance 32-bit digital DSP processor;

preferably, the insulation monitoring method of the photovoltaic system is applied to the photovoltaic system in claim 2, and specifically includes the following steps:

a. adopting a balanced and unbalanced bridge compatible detection mode to monitor the voltages to earth of the positive bus and the negative bus in real time in an isolated manner;

b. calculating the insulation resistance value of the bus by a direct-current voltage detection method;

c. when the bus insulation is lowered to a set value, starting branch inspection;

d. a branch power resistor RK is put into the bus, and the current of the current sensor is read through an RS485 bus;

e. collecting the voltage of a bus line to ground and the current value collected by each branch current sensor;

f. calculating the positive and negative grounding impedances of the branch by a branch leakage current detection method according to the data collected in the step e, and finishing the calculation of the positive and negative grounding resistances of each branch;

g. monitoring the condition that the positive and negative ends of the bus are reduced in resistance to the ground by using a resistor switching method;

h. and transmitting the collected resistance data into the switch, transmitting the resistance data to the background server, and monitoring and managing through background central centralized control.

The system for inhibiting potential attenuation and insulating monitoring manufactured by the technical scheme of the invention can inhibit and optimize the phenomena of poor power generation efficiency and battery pack performance attenuation (PID) of a photovoltaic power station; the photovoltaic power station direct current system insulation monitoring, early warning, alarming and alarming are carried out, so that the safe and reliable operation of equipment is better ensured, the fault time of the photovoltaic power station equipment is reduced, and the economic benefit of an owner is effectively improved; the intelligent remote monitoring function is used for mastering the operation data and the operation condition of each device on line in real time. The hidden trouble of equipment operation fault is discovered in time, and the information and intelligence are realized, so that the requirement of fine management is met; the photovoltaic power station has synergy, the power conversion efficiency of the photovoltaic array reaches more than 99.6%, the PID effect of the photovoltaic array is monitored, inhibited and repaired, and the annual energy production of the photovoltaic power station is comprehensively improved; safety: the system has a branch side insulation monitoring function, ensures stable and safe work and avoids the damage phenomenon of single-point grounding of the anode and the cathode. The system has the input and output isolation function, avoids the mutual influence among the strings, has the functions of short circuit, open circuit and attenuation early warning, and also has the surge impact protection function; intelligence: the system can realize the intelligent remote monitoring function and grasp the operation data and the operation condition of each device on line in real time. The hidden trouble of equipment operation trouble is found in time, and informationization, intellectuality reach the requirement of meticulous management.

Drawings

FIG. 1 is a schematic diagram of the structure of the suppression potential decay function of the photovoltaic system of the present invention;

FIG. 2 is a schematic view of the insulation monitoring function of the photovoltaic system of the present invention;

FIG. 3 is a schematic diagram of an insulation monitoring function ring network topology structure of the photovoltaic system of the present invention;

FIG. 4 is a schematic diagram of a substation room topology of the present invention;

FIG. 5 is a schematic flow chart of a method of using the inhibit potential decay function of the photovoltaic system of the present invention;

FIG. 6 is a schematic flow chart of a method of using the insulation monitoring function of the photovoltaic system of the present invention;

Detailed Description

The present invention is described in detail below with reference to the accompanying drawings, and as shown in fig. 1 to 6, the system for suppressing potential induced degradation effect includes a photovoltaic grid-connected inverter, a plurality of photovoltaic panels having the same structure are installed outside the photovoltaic grid-connected inverter, the photovoltaic panels are electrically connected to the photovoltaic grid-connected inverter, a potential induced degradation repair control device is installed between the photovoltaic panels and the photovoltaic grid-connected inverter, and the potential induced degradation repair control device is electrically connected to the photovoltaic grid-connected inverter and the photovoltaic panels, respectively. The photovoltaic system further includes: the cabinet converges, the cabinet that converges is installed outward to the photovoltaic grid-connected inverter, the cabinet that converges links to each other with the photovoltaic grid-connected inverter electrical property, converge the cabinet and install the same photovoltaic board of a plurality of structures outward, the photovoltaic board with converge and install the same current sensor of a plurality of structures between the cabinet, current sensor respectively with the photovoltaic board with it links to each other to converge the cabinet electrical property, converge the cabinet and install insulating detection device outward, theater detection device respectively with current sensor converge the case with the photovoltaic grid-connected inverter electrical property links to each other. The method for inhibiting potential decay of the photovoltaic system is applied to the photovoltaic system in claim 1, and comprises the following specific steps: a. a processor is adopted, and software and hardware are combined to form a PID repair control device with virtual resistance potential control; b. b, adding a self-adaptive series virtual resistance voltage source between the negative electrode of the photovoltaic system and the ground by using the PID repair control device in the step a; c. daytime mode was used when on the daytime and nighttime mode was used when on the night, the daytime state was analyzed. The daytime mode in the step c comprises the following specific steps: s1.1, using the PID repair control device to raise the low potential to the ground and serially connecting a high virtual resistor; and s1.2, inhibiting loss of positive ions of the back plate of the assembly and inhibiting attenuation of PID. The night mode in the step c comprises the following specific steps: s2.1, using the PID repair control device to perform high-voltage low-resistance PID recovery on all components of the system; and s2.2, inhibiting the loss of negative ions of the back plate of the assembly and inhibiting the attenuation of PID. The processor in the step a is a high-performance 32-bit digital DSP processor; the insulation monitoring method of the photovoltaic system is applied to the photovoltaic system in claim 2, and comprises the following specific steps: a. adopting a balanced and unbalanced bridge compatible detection mode to monitor the voltages to earth of the positive bus and the negative bus in real time in an isolated manner; b. calculating the insulation resistance value of the bus by a direct-current voltage detection method; c. when the bus insulation is lowered to a set value, starting branch inspection; d. a branch power resistor RK is put into the bus, and the current of the current sensor is read through an RS485 bus; e. collecting the voltage of a bus line to ground and the current value collected by each branch current sensor; f. calculating the positive and negative grounding impedances of the branch by a branch leakage current detection method according to the data collected in the step e, and finishing the calculation of the positive and negative grounding resistances of each branch; g. monitoring the condition that the positive and negative ends of the bus are reduced in resistance to the ground by using a resistor switching method; h. and transmitting the collected resistance data into the switch, transmitting the resistance data to the background server, and monitoring and managing through background central centralized control.

The following are the types and functions of the electric devices in the scheme:

a current sensor: the model is XZH-CS40, and is used for measuring the current condition of each branch circuit and calculating the leakage condition of each branch circuit.

PID repair control means: the model is XZH-RPID01 and is used for PID repair of the photovoltaic panel.

Insulating monitoring devices: the model is XZH-IM 01.

All the electrical components in the present application are connected with the power supply adapted to the electrical components through the wires, and an appropriate controller should be selected according to actual conditions to meet the control requirements, and specific connection and control sequences should be obtained.

In the embodiment, the intelligent synergistic system of the photovoltaic power station can effectively avoid the PID phenomenon of the component through integrating the PID protection module, and reduce the power generation loss of the power station. Meanwhile, the PID module has a repairing function, and can repair the assembly with the PID problem, so that all index parameters of the assembly are recovered to be normal.

Meanwhile, the intelligent synergy system of the photovoltaic power station can effectively and clearly display the insulation resistance value of each branch in real time, set an insulation resistance early warning value and an alarm value, and can take measures in advance when the value reaches the early warning value. And the insulation monitoring device also has the functions of communication interruption alarm, branch leakage current abnormity alarm and the like. Thereby guarantee the safe and reliable operation of equipment better, reduce the fault time of photovoltaic power plant equipment, effectively promote owner's economic benefits.

1. The system for inhibiting the PID effect adopts a high-performance 32-bit digital DSP processor, realizes a PID repair control device with virtual resistance potential control through the combination of software and hardware, inhibits 'loss' of positive ions after electrolysis of a backboard material under positive potential of system work by adding a self-adaptive series virtual resistance voltage source between a negative electrode of a photovoltaic system and the ground and improving the ground potential, and activates the lost positive charges of the backboard to restore the photovoltaic module to a normal state. After the equipment is connected into the system, the safety requirements of the ground and the system are obviously improved, and the safety damage caused by electric leakage can be effectively avoided. The system adopts a self-adaptive mode, namely, the ground potential of the system is improved, and meanwhile, the variable impedance is increased, so that the safety performance of the system is met. Under the daytime mode, the equipment raises low potential to the ground, is connected with a high virtual resistor in series, and inhibits loss of positive ions of a backboard of the assembly, namely inhibits attenuation of PID; in the night mode, performing high-voltage low-resistance PID recovery on all components of the system; through the two processes, the system PID can be effectively inhibited and recovered, and the power generation efficiency of the power station is improved. The structure of the system for inhibiting the PID effect is shown in FIG. 1:

2. the insulation monitoring system adopts a balance and unbalance bridge compatible detection mode to monitor the voltages to earth of the positive bus and the negative bus in real time in an isolated mode, and the bus insulation resistance value is calculated through a direct-current voltage detection method. When the insulation of the bus is lowered to a set value, the branch circuit is started to inspect, meanwhile, a branch circuit power resistor RK is put into the bus, and the current of the intelligent leakage current sensor is read through an RS485 bus. The system calculates the positive and negative grounding impedances of the branch circuit through a branch current leakage detection method according to the collected bus voltage to earth and the leakage current value collected by each branch circuit sensor, and the calculation of the positive and negative grounding resistances of each branch circuit is completed. Meanwhile, the condition that the positive and negative ends of the bus are reduced in resistance to the ground can be effectively monitored by using a method of switching the resistor. The insulation monitoring system structure is shown in fig. 2:

3. the ring network communication system and the intelligent synergy system exchange and transmit data through an industrial switch, adopt a standard TCP/IP protocol and an RJ45 physical interface, transmit acquired data into the switch in real time, and transmit the acquired data to a background server by utilizing a field ring network so as to facilitate monitoring and management of background central centralized control. Specific network topologies are shown in fig. 3 and 4.

The technical solutions described above only represent the preferred technical solutions of the present invention, and some possible modifications to some parts of the technical solutions by those skilled in the art all represent the principles of the present invention, and fall within the protection scope of the present invention.