In recent years, with the continuous deepening of carbon peak and carbon neutrality actions, the development of photovoltaics has achieved remarkable results. Under the guidance of national policies, various regions have set development goals for photovoltaics, and more and more enterprises and users are choosing to enter the photovoltaic industry.
Below, we have summarized the professional terms in the photovoltaic industry for your reference and learning. If you are also a photovoltaic person, these professional terms must be collected well!
Part 1: Common terms in the photovoltaic industry
Photovoltaic/Photovoltaic Effect
The full name is the photovoltaic effect, which is a phenomenon in which an object absorbs photons and generates an electromotive force. When an object is illuminated, the distribution of charges inside the object changes, resulting in an effect of electromotive force and current.
Photovoltaic power generation
A power generation technology that utilizes the photovoltaic effect to directly convert solar energy into electrical energy.
Measurement unit
Watt (W), kilowatt (kW), megawatt (MW), gigawatt (GW), terawatt (TW).
Calculation formula
1TW=1000GW=1000000MW=100000000kW=10000000000W.
The unit of energy for electricity
Kilowatt hour (kWh), which means 1 kWh of electricity is equivalent to 1 kWh of electricity.
Inverter
One of the key equipment in solar photovoltaic power generation systems, its function is to convert the direct current generated by solar cells into alternating current that meets the quality requirements of the power grid.
String inverter
A string inverter is a device that tracks the maximum power peak of several sets (usually 1-4 sets) of photovoltaic strings separately, and then merges them into the AC power grid after inversion. A string inverter can have multiple maximum power peak tracking modules with relatively low power, mainly used in distributed power generation systems and centralized photovoltaic power generation systems.
Installed capacity
After being connected in series and encapsulated for protection, solar cells can form large-area solar cell modules, which, when combined with power controllers and other components, form photovoltaic power generation devices. The power generated by this device is the installed capacity.
Capacity ratio
The ratio of component capacity to inverter capacity of a photovoltaic power station (capacity ratio=installed capacity of the photovoltaic system/rated capacity of the photovoltaic system). Appropriately increasing the capacity ratio within a certain range can improve the utilization rate of other equipment, dilute investment costs, reduce costs and power generation costs, and also make output smoother, improving grid friendliness.
AGC
Automatic Generation Control (AGC), also known as active power control system, responds to the remote control instructions issued by the dispatch and optimizes the calculation of the overall strategy through the AGC module to ensure that the operating data meets the requirements of dispatch and grid connection.
AVC
Automatic Voltage Control, also known as reactive voltage regulation, quickly responds to dispatch instructions based on the voltage curve of the power grid, automatically adjusts control strategies and response times such as reactive power and reactive compensation devices to achieve voltage regulation goals and reduce network losses.
Low voltage ride through technology for photovoltaic power plants
It refers to the ability of photovoltaic power plants to continuously connect to the grid within a certain range when voltage fluctuations at the grid connection point are caused by power grid faults or disturbances.
Average conversion efficiency
A measure of the ability of solar cells to convert light energy into electrical energy. The ratio of the optimal output power of a solar cell to the solar radiation power projected onto its surface.
Leveling the cost of electricity
Abbreviated as electricity cost per kilowatt hour. Leveling the costs and power generation during the project lifecycle, and then calculating the power generation cost, which is the present value of costs during the lifecycle divided by the present value of power generation during the lifecycle.
Affordable internet access
It includes two levels of meaning: power generation parity and user parity. Power generation parity refers to the ability of photovoltaic power generation to achieve reasonable profits even if purchased at the grid price of traditional energy sources (without subsidies); User side parity refers to the situation where the cost of photovoltaic power generation is lower than the selling price of electricity. Depending on the type of user and their purchasing cost, it can be divided into commercial and residential user side parity.
Benchmark on grid electricity price
The National Development and Reform Commission has set the purchase price (including tax) for centralized photovoltaic power plants connected to the grid by power grid companies.
Utilization hours of power generation equipment
The average operating hours of a region's power generation equipment capacity under full load conditions during a certain period of time, that is, the ratio of power generation to average installed capacity, reflects the utilization rate of the region's power generation equipment. The formula is: utilization hours=power generation/installed capacity.
Annual utilization hours
The average full load operation time of the generator set within one year; The proportion of utilization hours of power generation equipment in 8760 hours per year, also known as "equipment utilization rate".
Dedicated line access
Distributed power access points are equipped with dedicated switch devices for distributed power, such as direct connection of distributed power to substations, switching stations, distribution room busbars, or ring main units.
Collector line
In a photovoltaic power generation system with decentralized inverters and centralized grid connections, the electrical energy output from each photovoltaic module string is converged to the inverter through a combiner box, and then collected to the DC and AC transmission lines of the power generation busbar through the inverter output terminal, which is called a collection line. The transmission of collection lines can be carried out through overhead, direct burial, or bridge laying methods.
Combiner box
It can be divided into DC combiner box and AC combiner box. DC combiner box is a wiring device that ensures orderly connection and combiner function of photovoltaic modules; The AC combiner box is used to converge the output currents of multiple inverters, while protecting the inverters from harm from the AC grid side/load. As an output disconnection point for the inverters, it improves the safety of the system and protects the safety of installation and maintenance personnel.
High, medium and low voltage grid connection of photovoltaic power plants
General industrial and commercial enterprises with 400kW and below can perform low-voltage 380V grid connection. Multiple grid connection points can be established between 400kW-2MW for low-voltage grid connection. If the power exceeds 2MW, 10kV grid connection is required, and if it exceeds 6MW, 35kV grid connection is required (refer to the requirements or recommendations of the local power grid company for details).
AC/DC cable
Power sources are divided into AC and DC, so they are divided into AC cables and DC cables. AC cables are cables used to connect AC power sources; DC cables are used as cables in DC power transmission and distribution systems.
Single crystal solar cell
A solar cell developed based on high-quality monocrystalline silicon materials and processing techniques, generally using surface texturing, emitter passivation, and zone doping technologies.
Polycrystalline solar cells
Using solar grade polycrystalline silicon materials and manufacturing processes similar to monocrystalline silicon solar cells, the current photoelectric conversion efficiency and production cost are slightly lower than monocrystalline solar cells.
Part 2: Terminology related to photovoltaic modules
Module
Solar modules are composed of several solar power generation units connected in series and parallel. Its function is to amplify low-power solar power generation units into standalone optoelectronic devices, usually with high power, which can charge various types of batteries separately, or be used in series or parallel as power generation units for off grid or grid connected solar power supply systems.
Stacked tiles
The stacked tile component is an advanced technology component designed by dividing battery cells and bonding them to each other through conductive adhesive to form a dense arrangement. Replacing traditional technology with solder strips to enhance the effective power generation area of battery cells.
Double sided components
A component that can utilize light that is incident on both the front and back sides to generate light energy. Normally, the backside power of a double-sided component is over 60% of the frontal power.
Double sided double glass component
Components prepared using double-sided batteries and double-sided glass.
Photovoltaic bracket
Special functional brackets used for installing, supporting, and fixing photovoltaic modules in photovoltaic power generation systems, including tracking brackets and fixed brackets.
Tracking bracket/tracking system/tracker
A device that adjusts the spatial angle of the solar module plane relative to the incident sunlight in real time through the combined action of mechanical, electrical, electronic circuits, and programs, in order to increase the amount of sunlight projected onto the module and improve power generation.
Long term photoinduced attenuation (LID)
The attenuation of battery and component output power caused by prolonged exposure to light.
PID
Potential induced degradation refers to the leakage current between glass and packaging materials caused by long-term exposure of components to high voltage, resulting in a large amount of charge accumulating on the surface of the battery cell and deteriorating the passivation effect of the battery surface, leading to component performance below design standards.
STC
Standard Test Conditions, mainly used in laboratories, refer to an ambient temperature of 25 ℃, atmospheric quality of AM1.5, wind speed of 0m/s, and 1000W/m ².
NOCT
Normal Operating Cell Temperature, the NOCT of normal components is at 45 ℃± 2 ℃. It refers to the temperature reached when the solar module or battery is in an open circuit state and at (battery surface light intensity=800W/m ², ambient temperature=20 ℃, wind speed=1m/s).
BIPV
Building Integrated Photovoltaic, the photovoltaic materials used in photovoltaic buildings are reflected in the form of building materials, so photovoltaic building materials not only undertake power generation functions, but also serve building functions. Composite solar cells with building materials and directly apply them to the enclosure structures such as roofs and walls of buildings.
BAPV
Building Attached Photovoltaic is defined differently from BIPV. Mainly refers to solar photovoltaic power generation systems installed on existing buildings, also known as "installation type" solar photovoltaic buildings. The main function of BAPV is power generation, which does not conflict with the functions of buildings and does not damage or weaken the functions of existing buildings.
PERC
Emitter passivation and backside contact battery. PERC cells have a market share of about 90% and are currently the most mainstream type of solar cells in the market.
TOPcon
Tunneling oxide passivation contact battery, N-type battery technology, with high theoretical efficiency limit and similar process to PECR.
HJT
Heterojunction cells with amorphous layers use different semiconductor materials to form heterogeneous PN junctions, which have high theoretical efficiency, few processing steps, but extremely high process requirements.
IBC
Cross finger back contact battery.
Part Three: Operation Mode of Photovoltaic Power Station
Ground power station/centralized power station
The main use of large-scale solar cell arrays is to directly convert solar energy into direct current, which is then connected to the power grid through AC distribution cabinets, step-up transformers, and high-voltage switchgear to deliver photovoltaic power to the grid, which is then uniformly distributed by the grid to supply power to users.
Distributed power station
A photovoltaic power generation project located near the user, where the generated energy is utilized on-site and connected to the grid at voltage levels below 35kV or lower, and the total installed capacity of a single grid connection point generally does not exceed 6MW.
Intelligent power station
It refers to the deep integration with 5G, Internet, big data, artificial intelligence and other new generation information technologies in the application of photovoltaic field, so that all links of photovoltaic power station from construction to operation can be helped by digital technology to maximize the value of customers who hold and operate the power station.
Self use and surplus electricity connected to the internet
This photovoltaic system mode is the most common mode, and generally distributed photovoltaic power generation systems mainly adopt this mode. The electricity generated by photovoltaic systems can first meet their own load usage, and excess electricity can be sold to the grid to avoid waste; If the electricity generated by photovoltaics is insufficient for load use, it will be supplemented by power supply from the grid. This model involves the installation of bidirectional smart meters in the power grid, which respectively measure the power generation of photovoltaic power plants and the electricity consumption of users, and pay or collect electricity bills according to policies and negotiated electricity prices.
Self use, no internet connection for surplus electricity
The significant feature of the spontaneous self use grid connection mode is "grid connection without grid connection". The access point of this mode is located at the lower end of the power grid meter, which is the private side of the complete property boundary point. This photovoltaic system mode is generally applied in situations where the user side has a large and continuous electricity load, and the user has the ability to use up the photovoltaic power generation without causing waste.
Full internet access
This grid connection mode directly connects the AC output of the photovoltaic system to the low-voltage or high-voltage side of the power grid, which is the grid side where property rights are divided. The electricity generated by this system is directly sold to the grid, and the sales price is usually based on the local average grid electricity price. The user's electricity price remains unchanged, as the saying goes, "there are two lines of income and expenditure, each accounting for its own account". This mode of directly selling electricity online is also the mainstream of photovoltaic applications; Because its financial model is simple, relatively reliable, and easily favored by investors.