Under the "support" of various policies, the construction of photovoltaic power stations is in full swing, and the safety issue is the top priority. According to the report, connector damage and burn out ranked second among the power plant's TOP20 technology failure risks in terms of lost revenue.
In the context of achieving the "double carbon target", it is expected that in the next five years, the annual newly installed photovoltaic capacity in China will reach 62 to 68GW, and the cumulative installed capacity of photovoltaic power stations in China will reach 561GW in 2025.
It can be predicted that whether it is ground power station or distributed power station, the installed volume of photovoltaic will enter the stage of large-scale growth, but with the "safety problem" is also more and more, causing the attention and attention of the industry.
Safety is the lifeblood of photovoltaic power plants and the foundation for return on investment. No matter in the ground, mountain, roof and other photovoltaic power station scenarios, "safety" is a vote of no principle.
Three accidents "hidden dangers" in photovoltaic power station
In view of photovoltaic safety accidents, Xie Jin, TE's new energy industry business development & Key account manager, believes that there are three main reasons for photovoltaic power station accidents:
First, photovoltaic module connector, commonly known as DC connector. As the component power increases, so does the current. In this case, the component connector heats up more and more, creating a fire hazard. Therefore, the connector of the component is one of the most fire prone points in the DC side link of the component.
Second, the DC bus box. In the DC junction box is arranged with dense lines and electrical appliances, plus a closed metal box. In the sealed structure environment, electrical appliances and connection points in the box heat will be relatively high, and not easy to dissipate heat, in the case of long-term operation, easy to appear electrical heating, tripping and other problems, become the hidden danger of fire.
Third, medium and high voltage cable joint. In the power station, 35 kV medium voltage electrical system and 110kV/220kV high voltage boost system are common. The voltage level of medium and high voltage products is relatively high, and cable accessories are prone to local release and breakdown problems. Therefore, this is also one of the hidden dangers of photovoltaic power station accidents.
Connectors ranked second among the Top20 technical failures in power stations
From the above three reasons, analysis can be seen that the connector brought by the security risks can not be ignored! Otherwise, accidents such as connector fire, burn out, junction box failure, component leakage, and power failure of the cluster components may occur later.
According to a report released by the Solar Bankability project of the European Union Horizon2020 program, damage to solar cable connector and burning of Solar cables ranked second among the TOP20 power plant technology failure risks in terms of lost power generation revenue.
Why are connectors so important?
Use a large number. Connectors are used in PV systems from components to inverters to engineering sites. For a 1MW PV system, about 2,000 to 3,000 sets of connectors are used, depending on the power of the components used.
High potential risks. Each set of connectors contains 3 risk points (connection, positive and negative and cable crimp), which means that for a 1MW system, the connectors may introduce 6000 to 9000 risk points. In the case of throughflow, the increase of the contact resistance of the connector will lead to the increase of temperature rise. If the temperature range is beyond the tolerance of the plastic shell and metal parts, the connector is easy to fail and even causes fire.
On-site operation and maintenance is difficult. Most of the existing monitoring software can only monitor the group level. For the specific faults in the cluster, on-site inspection is still required. This means that if there is a problem with the connector, it must be checked one by one. For industrial and commercial power stations (colored steel tile roof), operation and maintenance is more difficult. workers need to climb on the roof, and then manually lift the panels, time-consuming and laborious.
The power consumption is large. The connector itself does not produce energy; it is a transmitter of energy. In the process of energy transmission, there will be losses. If the average contact resistance of a commercial connector is calculated, a 50MW power station will lose about 2.12 million degrees of power due to the connector during its 25 years of operation.
This year, driven by the policy, the construction of photovoltaic power stations is in full swing, carbon neutral, carbon peak target can be expected, but the premise of all this must be safe. Connector enterprises also need to put forward innovative solutions to the problem of safety, so that the photovoltaic power station in the operation process to reduce the occurrence of safety accidents, but also let our carbon neutral road go more stable and steady.