Small and medium-sized photovoltaic power plants are characterized by small footprint, flexible installation location and low daily maintenance. Due to the different operating environments of photovoltaic power plants, in order to make the photovoltaic power generation system safer and more stable, improve power generation efficiency, and increase user benefits, this operation and maintenance manual is specially compiled to facilitate personnel with certain professional knowledge when conditions permit Properly maintain the power station.
1. Operation and maintenance management of distributed photovoltaic power plants
1.1 Establish a sound technical document management system
Technical documents mainly include:
(1) Establish the equipment technical files and design and construction drawing files of the power station;
(2) Establish an information management system for the power station;
(3) Establish the operating period files of the power station.
1.2 Establish technical files of power station equipment and design and construction drawings files
mainly include:
(1) Design and construction, as-built drawings;
(2) The basic working principle of the equipment, technical parameters, equipment installation procedures, and equipment debugging steps;
(3) Description of all operating switches, knobs, handles, status and signal indications;
(4) Operation steps of equipment operation;
(5) Items and contents of power station maintenance;
(6) Maintenance schedule and operating procedures for all maintenance items.
1.3 Establish an information management system
(1) Use digital information technology to uniformly calibrate and process the information collection, transmission, processing, and communication of photovoltaic power plants, integrate photovoltaic power plant equipment monitoring and management, condition monitoring management systems, and comprehensive automatic protection systems to realize photovoltaic power plant data sharing and remote monitor.
(2) Photovoltaic power plant monitoring systems are generally divided into two categories:
a. One is a distributed monitoring system of a wireless network. It is generally used in small and medium-sized rooftop photovoltaic power stations that are distributed in installation areas and adopt block-based power generation and low-voltage distributed grid connection. Because it uses GPRS wireless public network transmission, data stability and security cannot be guaranteed. Therefore, it is generally not applied to photovoltaic power stations with a voltage level of 10 KV and above.
b. The other is a centralized monitoring system for optical fiber networks. Generally used in large-scale ground photovoltaic power stations, or rooftop photovoltaic power stations with grid-connected voltage levels of 10KV and above.
2. Information Management System
2.1 Distributed monitoring system of wireless network
(1) Each monitoring sub-station collects the data of photovoltaic grid-connected inverters, electricity meters and weather stations through RS485 communication, and sends the data to the relevant local server or remote server through various communication means such as Ethernet/WiFi/GPRS, and then Data display through the web client.
(2) Users can also log in to remote servers for real-time remote access to data, and display data through network clients, smart phones, and tablet computers.
2.2 Relevant management systems and standards-foundations of information systems
(1) Clarify the relevant management system and operation and maintenance manual of grid-connected photovoltaic power plants;
(2) Establish relevant national, local and industry standards for the operation and maintenance of photovoltaic power plants
2.3 Strengthen personnel training
Mainly aimed at two aspects of personnel:
(1) Conduct training for technical personnel in the industry, and organize the technical personnel to conduct internal training on various topics in response to the key and difficult problems in operation and maintenance management, and send the technical personnel out for systematic related knowledge training. Improve the professional skills of professional technicians;
(2) Train the operators of the power station. After the training, they should understand and master the basic working principles of the photovoltaic power generation system and the functions of each equipment, and be able to carry out the daily maintenance of the power station as required, and be able to judge general faults. The reason and the ability to solve it.
2.4 Establish an unobstructed information channel
(1) Establish a dedicated person to be responsible for contacting power station operators and equipment manufacturers. When the power station breaks down, the operator can promptly submit the problem to the relevant departments, and at the same time can notify the equipment manufacturer and maintenance personnel to go to the site for repairs in the shortest time.
(2) For each power station, a comprehensive and complete technical document file must be established, and a special person shall be set up to be responsible for the management of the power station's technical documents to provide strong technical basic data support for the safe and reliable operation of the power station.
3. Daily maintenance of photovoltaic power station
3.1 Photovoltaic modules and brackets
(1) The surface of the photovoltaic module should be kept clean. Use dry or damp soft and clean cloth to wipe the photovoltaic module. It is strictly forbidden to wipe the photovoltaic module with corrosive solvents or hard objects; the irradiance should be less than 200W/m2 To clean photovoltaic modules, it is not advisable to use liquids that have a large temperature difference with the modules to clean the modules;
(2) Photovoltaic modules should be inspected regularly. If the following problems are found, they should be adjusted or replaced immediately;
a. Photovoltaic modules have broken glass, burning of the backplane, obvious color changes, etc.;
b. The junction box is deformed, twisted, cracked or burned in the photovoltaic module, and the junction terminal cannot be connected, etc.;
(3) The live warning mark on the photovoltaic module must not be lost.
(4) For photovoltaic modules with metal frames, the frame and the support should be well combined, the contact resistance between the two should not be greater than 4Ω, and the frame must be firmly grounded.
(5) When working under the condition of no shade, under the condition that the solar radiation is above 500W/m2 and the wind speed is not more than 2m/s, the temperature difference on the outer surface of the same photovoltaic module (area directly above the battery) should be less than 20℃. Photovoltaic power plants with installed capacity greater than 50kWp should be equipped with infrared thermal imaging cameras to detect the temperature difference on the outer surface of photovoltaic modules.
(6) Use a DC clamp-type ammeter to measure the input current of each photovoltaic module string connected to the same DC combiner box under the condition that the solar radiation intensity is basically the same, and the deviation should not exceed 5%.
(7) Maintenance of the bracket
a. All bolts and bracket connections should be firm and reliable
b. The anti-corrosion coating on the surface of the bracket should not crack or fall off, otherwise it should be repainted in time
c. The support should be well grounded, and the grounding system should be inspected before the arrival of the thunderstorm season each year. Mainly check whether the connection is firm and the contact is good
d. The planting ribs or expansion bolts used to fix the photovoltaic support should not be loose. Photovoltaic brackets installed on a prefabricated base, the prefabricated base should be placed stably and neatly, and the position must not be moved
3.2 Cleaning of photovoltaic modules
(1) In recent years, the annual installed capacity of photovoltaic power plants has increased year by year, and the national subsidy policy has evolved from "golden sun" and "photovoltaic buildings" to electricity price subsidies. Therefore, the power generation capacity of the power station is very important, and the dust on the components affects the power generation capacity. One of the important factors.
Comparison of components before and after cleaning
After cleaning, the power generation of the power station is increased by 5%-30%, and the cleaning frequency ranges from ten times a year or once a month.
(2) Cleaning method
a. Manual cleaning (this is currently the most widely used method)
Advantages: low cost
Disadvantages: difficult to manage for personnel; poor cleaning effect; wear and tear on the component glass; affect light transmittance and life.
b. High pressure water gun cleaning
Advantages: good cleaning effect
Disadvantages: large water consumption; 1MW water consumption is about ten tons; excessive pressure of the water gun will cause component cracking; it cannot be used in mountainous areas where vehicles cannot drive.
c. Professional equipment cleaning
Advantages: small water consumption; fast cleaning speed and good effect
Disadvantages: It is suitable for sites with a wide distance between the front and rear of the module; the non-linear movement of the vehicle with the vehicle causes uneven pressure on the module; professional operation is required.