These photovoltaic professional terms you have to know !
In recent years, as carbon peaking and carbon neutrality actions continue to gain popularity, my country’s photovoltaic development has achieved remarkable results. Under the guidance of national policies, various regions have proposed photovoltaic development goals, and more and more companies and users have chosen to enter the photovoltaic industry.
Below, Photovoltaic Tantan has summarized the professional terms in the photovoltaic industry for your reference and study. If you are also a photovoltaic person, you must keep these professional terms in your collection!
Part 1: Common terms in the photovoltaic industry
Photovoltaic/photovoltaic effect
The full name is photovoltaic effect, which is the phenomenon that an object generates electromotive force due to the absorption of photons. When an object is exposed to light, the charge distribution state inside the object changes, producing an effect of electromotive force and current.
PV
A power generation technology that utilizes the photovoltaic effect to directly convert solar energy into electrical energy.
unit of measurement
Watt (W), kilowatt (kW), megawatt (MW), gigawatt (GW), terawatt (TW).
Calculation formula
1TW=1000GW=1000000MW=1000000000kW=1000000000000W.
unit of electrical energy
Kilowatt hour (kWh), that is, 1kWh of electrical energy is 1 kilowatt hour of electricity.
Inverter
One of the key equipments in the solar photovoltaic power generation system, its function is to convert the DC power emitted by the solar cells into AC power that meets the power quality requirements of the grid.
String inverter
The string inverter tracks several groups (usually 1-4 groups) of photovoltaic strings to individually track the maximum power peak, and then integrates them into the AC grid after inversion. A string inverter can have multiple maximum power peak tracking modules with relatively small power. It is mainly used in distributed power generation systems and centralized photovoltaic power generation systems.
Installed capacity
Solar cells can be packaged and protected after being connected in series to form a large-area solar cell module. Together with power controllers and other components, a photovoltaic power generation device is formed. The power generated by this device is the installed capacity.
Volume ratio
The ratio of the component capacity of the photovoltaic power station to the inverter capacity (capacity ratio = photovoltaic system installed capacity/photovoltaic system rated capacity). Appropriately increasing the capacity-to-distribution ratio within a certain range can improve the utilization rate of other equipment, dilute investment costs, reduce construction costs and power generation costs. It can also make the output smoother and improve grid friendliness.
AGC
Automatic Generation Control (Automatic Generation Control), that is, the active power control system, responds to the remote adjustment instructions issued by the dispatcher and optimizes the calculation through the overall strategy of the AGC module to make the operating data meet the dispatching and grid connection requirements.
AVC
Automatic Voltage Control (Automatic Voltage Control), that is, reactive voltage regulation, quickly responds to dispatch instructions according to the grid voltage curve, automatically adjusts control strategies and response times such as reactive power and reactive power compensation devices, and achieves voltage regulation targets and reduces network losses. .
Photovoltaic power station low voltage ride-through technology
It means that when the voltage at the grid connection point of the photovoltaic power station fluctuates due to grid failure or disturbance, within a certain range, the photovoltaic power station can operate uninterruptedly on the grid.
average conversion efficiency
A measure of a solar cell’s ability to convert light energy into electrical energy. The optimal output power of a solar cell is the ratio of the solar radiation power projected onto its surface.
Levelized cost of electricity
Referred to as cost of electricity. The cost and power generation during the life cycle of the project are first levelized, and then the power generation cost is calculated, that is, the present value of the cost during the life cycle/the present value of power generation during the life cycle.
Affordable Internet access
It includes two meanings: power generation side parity and user side parity. Generation-side parity refers to the fact that photovoltaic power generation can achieve reasonable profits even if it is purchased according to the feed-in price of traditional energy (without subsidies); user-side parity refers to the fact that the cost of photovoltaic power generation is lower than the electricity sales price. According to the type of users and their electricity purchase costs, Different, it can be divided into industrial and commercial and residential user-side parity.
Benchmark on-grid electricity price
The National Development and Reform Commission sets the purchase price (tax included) for power grid companies to purchase electricity from centralized photovoltaic power stations connected to the grid.
Power generation equipment utilization hours
The number of operating hours of the average power generation equipment capacity in a region under full load operating conditions within a certain period, that is, the ratio of power generation to the average installed capacity, reflects the utilization rate of power generation equipment in the region. The formula is: utilization hours = power generation/installed capacity.
Yearly utilization hours
The average full-load operating time of the generating set within one year; among the 8,760 hours per year, the proportion of power generation equipment utilization hours is also called “equipment utilization”.
Dedicated line access
Distributed power access points are equipped with switching equipment dedicated to distributed power, such as distributed power directly connected to substations, switching stations, power distribution room busbars, or ring network cabinets.
collector circuit
In a photovoltaic power generation system with decentralized inversion and centralized grid-connection, the electric energy output by each photovoltaic module string is combined to the inverter through the combiner box, and then collected to the power generation bus through the inverter output terminal. The DC and AC transmission lines are called collector circuit. The current collection line can be sent out by overhead, direct burial or bridge laying.
Combiner box
It can be divided into DC combiner box and AC combiner box. The DC combiner box is a wiring device that ensures the orderly connection and convergence function of photovoltaic modules; the AC combiner box combines the output currents of multiple inverters while protecting the inverters from harm from the AC grid-connected side/load. As an inverter The output disconnection point of the transformer 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
Generally, industrial and commercial projects of 400kW and below can be connected to the low-voltage 380V grid. Between 400kW and 2MW, multiple grid-connected points can be used for low-voltage grid connection. If it exceeds 2MW, it needs to be connected to the grid at 10kV. If it exceeds 6MW, it needs to be connected to the grid at 35kV (please refer to the local power grid company for details). requests or suggestions).
AC and DC cables
The power supply is divided into AC and DC, so it is divided into AC cable and DC cable. AC cables are used to connect AC power supply cables; DC cables are used to connect cables in DC power transmission and distribution systems.
Monocrystalline solar cells
A solar cell based on high-quality monocrystalline silicon materials and processing techniques, generally developed using technologies such as surface texturing, emitter area passivation, and zoned doping.
polycrystalline solar cells
Using solar-grade polysilicon material, the manufacturing process is similar to that of 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
components
Solar modules are composed of several solar power generation units connected in series and parallel. Its function is to amplify a small-power solar power generation unit into a photovoltaic device that can be used alone. It usually has a large power and can charge various types of batteries alone. It can also be used in series or parallel with multiple units as an off-grid or grid-connected solar power supply. The power generation unit of the system.
imbricate
The shingled module is an advanced technology component with an overlapping and close-packed design after the cells are cut into pieces and bonded to each other with conductive adhesive. It replaces the traditional soldering technology and enhances the effective power generation area of the battery cells.
Double sided module
A component that utilizes light incident on the front and back to generate light energy. Normally, the back power of a bifacial module is more than 60% of the front power.
Double-sided double glass module
Components made of double-sided cells and double-sided glass.
Photovoltaic bracket
Special function brackets used to install, support and fix photovoltaic modules in photovoltaic power generation systems, including tracking brackets and fixed brackets.
Tracking stand/tracking system/tracker
Through the joint action of mechanical, electrical, electronic circuits and programs, the spatial angle of the solar module plane relative to the incident sunlight is adjusted in real time to increase the amount of sunlight projected onto the module and thereby increase power generation.
Long-term light-induced degradation (LID)
The attenuation of the output power of batteries and components caused by prolonged exposure to sunlight.
PID
Potential-induced degradation (potential potential-induced degradation), that is, the component is exposed to high voltage for a long time, causing leakage current between the glass and packaging materials, and a large amount of charge accumulates on the surface of the battery sheet, which worsens the passivation effect on the battery surface and reduces the performance of the component. Below design standards.
STC
Standard Test Conditions, mainly used in laboratories, refer to ambient temperature at 25°C, air quality AM1.5, wind speed = 0m/s, 1000W/m².
NOCT
Normal Operating Cell Temperature (rated battery operating temperature), the NOCT of normal components is 45℃±2℃. It refers to the temperature reached when the solar module or battery is in an open circuit state and (battery surface light intensity = 800W/m², ambient temperature = 20°C, wind speed = 1m/s).
BIPV
Building Integrated Photovoltaic (photovoltaic building integration), the photovoltaic materials used in photovoltaic buildings are embodied in the form of building materials, so photovoltaic building materials not only bear the function of generating electricity, but also perform the function of construction. Solar cells are combined with building materials and directly applied to building roofs, walls and other surrounding structures.
BAPV
Building Attached Photovoltaic (Building Attached Photovoltaic) is defined differently from BIPV. Mainly refers to solar photovoltaic power generation systems installed on existing buildings, also known as “installed” solar photovoltaic buildings. The main function of BAPV is to generate electricity, which does not conflict with the functions of the building and does not damage or weaken the functions of the original building.
PERC
Emitter passivation and back contact cell. PERC batteries account for about 90% of the market and are the most mainstream battery type in the current market.
TOPcon
Tunnel oxide layer passivation contact battery, N-type battery technology, with high theoretical efficiency limit, and the process is similar to PECR.
HJT
Heterojunction cells with amorphous layers use different semiconductor materials to form heterojunctions. They have high theoretical efficiency and few processing steps, but the process requirements are extremely high.
IBC
Interdigitated back contact battery.
Part 3: Photovoltaic power plant operation model
Ground power station/centralized power station
It mainly uses large-scale solar cell arrays to directly convert solar energy into DC power, and connects to the power grid through AC distribution cabinets, step-up transformers and high-voltage switching devices, and transmits photovoltaic power to the power grid, which is uniformly deployed by the power grid to provide power to users.
Distributed power station
It refers to a photovoltaic power generation project that is located near the user, uses the generated energy locally, and is connected to the power grid at a voltage level of less than 35kV or lower, and the total installed capacity of a single grid-connected point generally does not exceed 6MW.
Smart power station
Refers to the deep integration with new generation information technologies such as 5G, Internet, big data, and artificial intelligence in applications in the photovoltaic field, so that all aspects of photovoltaic power stations from construction to operation can be helped by digital technology to realize power station ownership and operation. Maximize customer value.
Spontaneous self-use and surplus electricity for online use
This photovoltaic system mode is the most common mode, and generally distributed photovoltaic power generation systems mainly adopt this mode. The power generated by the photovoltaic system can first meet its own load use, and the excess power can be sold to the grid to avoid waste; if the power generated by the photovoltaic system is insufficient for the load, it will be supplemented by power supply from the grid. In this model, the power grid installs two-way smart meters to measure the power generation of the photovoltaic power station and the user’s electricity consumption respectively, and pay or collect electricity fees based on policies and negotiated electricity prices.
Spontaneous self-use, surplus electricity not connected to the Internet
The distinctive feature of the spontaneous and self-use grid-connected mode is “connected to the grid but not connected to the Internet”. The access point of this model is at the lower end of the power grid meter, which is the complete private side of the property rights demarcation point. This photovoltaic system mode is generally used when the electricity load on the user side is large and the electricity load is continuous. The user is fully capable of using up the photovoltaic power generation without causing waste.
Full Internet access
This grid-connected mode directly connects the AC output of the photovoltaic system to the low-voltage side or high-voltage side of the grid, which is the grid side where property rights are demarcated. In this way, the electricity generated by the system is directly sold to the power grid, and the sales price usually adopts the local average on-grid electricity price. The user’s electricity price remains unchanged. The so-called “two lines of income and expenditure, each calculates its own price” Account”. This model of directly selling electricity online is also the mainstream of photovoltaic applications; because its financial model is simple and relatively reliable, it is easily favored by investors.
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