Environmental adaptability analysis of energy storage equipment in deserts, Gobi, deserts and other areas

In the desert, the Gobi, desert areas building wind and photovoltaic base projects is the main way to develop centralized new energy, while through the supporting construction of energy storage to achieve efficient utilization of new energy, clean power of the new energy base can be sent to the load terminal through UHV lines, through the construction of energy storage at the source can improve the power quality and transmission efficiency of new energy power generation.

In November 2021, the National Energy Administration and the National Development and Reform Commission issued the "Notice of the First List of Large-scale Wind Power and Photovoltaic Base Construction Projects Focusing on Desert, Gobi and Desert Areas", involving 19 provinces and a total scale of 97.05GW; In December 2021, the National Energy Administration once again issued the "Notice on Organizing the Second Batch of Large-scale Wind Power photovoltaic Base Projects Focusing on Desert, Gobi, and Desert Areas" to accelerate the construction of wind and solar power base projects.

This month, the National Development and Reform Commission publicly stated that it will vigorously promote the construction of large-scale wind power photovoltaic bases focusing on the desert, Gobi and desert areas, and the first batch of projects has started more than 95GW, the first batch of projects have basically started, and the second batch of base projects have also been started.

Desert, Gobi, desert areas as the "main battlefield" of new energy construction, its site to Qinghai, Ningxia, Inner Mongolia, Gansu, Xinjiang, Shaanxi and other northwest regions, the natural environment is relatively complex and harsh, often facing high altitude, low temperature, strong wind and sand, and other special environment impacts, the environmental adaptability of energy storage equipment also put forward special requirements.

High altitude refers to areas above 1000 meters above sea level, for example, the altitude in Qinghai is generally around 3000 meters. With the increase of altitude, the air thinning and air pressure decrease, the strength of the external insulator of the electrical appliance decreases, the live gap of the external insulation surface and different potentials is easy to break down, and at the same time, for the switching appliance with air as the arc extinguishing medium, the arc extinguishing ability decreases, resulting in a decrease in the on-off ability. Therefore, electrical design and equipment selection need to consider the influence of high altitude factors. According to the requirements of the regulations, when the altitude is higher than 1000 meters but less than 4000 meters, for every 100 meters increase in altitude, the external insulation strength is reduced by about 1%, so it is generally necessary to strengthen the insulation or adopt high prototype electrical equipment. At the same time, the safety net distance of electrical equipment also needs to be corrected according to the altitude.

For example, at altitudes below 1000 meters, the minimum safety net distance between and relative to 35kV outdoor power distribution devices is 400mm; The minimum safe net distance between phases and relatives at an altitude of 2000 meters needs to be corrected to 440 mm; The minimum safe net distance between phases and relatives at altitudes of 3000 m needs to be corrected to 470 mm.

The minimum temperature in winter in cold areas such as Inner Mongolia, Xinjiang, Qinghai and so on is usually below -20 °C, and the extremely low temperature can reach about -40 °C. As we all know, the low-temperature performance of lithium iron phosphate batteries is poor, the activity of the battery decreases at low temperatures, the embedding and shedding capacity of lithium decreases, and the usable capacity of the battery decreases. Taking a battery as an example, the capacity retention rate is 100% at 25 °C, the capacity retention rate is about 80% at 0 °C, and the capacity retention rate at -20 °C is only about 55%. Operating ambient temperature has a great impact on the usable capacity of energy storage batteries, in order to ensure the efficient use of energy storage systems, generally maintain the operating ambient temperature of electric energy storage equipment at about 15-25 ° C, in a low-temperature environment, generally through the battery compartment to take thermal insulation measures, the configuration of heaters and other measures to ensure the safe and efficient operation of energy storage equipment.

In the desert and other areas, energy storage power station equipment is usually also facing the invasion of wind and sand, because the energy storage system generally adopts the outdoor integrated arrangement scheme of the cabin or cabinet type, the inlet and outlet of outdoor equipment such as battery compartment, energy storage converter transformer complete sets of equipment in a strong wind and sand environment, if the equipment protection level does not meet the requirements, fine sand and dust into the interior of the equipment may lead to a decline in electrical insulation performance, poor contact with switch equipment contacts, secondary equipment failure, and the accumulation of sand and dust will even cause serious failures such as electrical short circuits. Poses a threat to the safe operation of energy storage systems. Therefore, the overall protection design of outdoor equipment needs to fully consider the influencing factors of wind and sand, such as the use of measures such as sealing, the sealing agent at the connection, sand-proof cotton in the inlet and outlet, and reasonable setting of the wind direction of the air duct. At the same time, in the process of installation and maintenance, do a good job of dust-proof measures, reduce the frequency of opening doors and windows, and avoid sand and dust entering the inside of the equipment, especially non-walk-in energy storage equipment, it is necessary to consider the windproof sand measures for installation, commissioning and maintenance outside the cabin.

Humidity, temperature, pollution, altitude, dust and other environmental conditions have a significant impact on whether the energy storage equipment can operate safely and reliably during the life cycle, especially the impact on safety should become the focus, energy storage equipment selection needs to understand the various natural conditions of the project location in advance and put forward design index values, such as altitude, annual extreme minimum temperature, sandstorm days, etc., consider various influencing factors in the production of equipment, and put forward guiding measures for the environmental adaptability of later operation and maintenance.