On February 7, the first domestic supercapacitor micro-energy storage device independently developed by State Grid Jiangsu Electric Power Co., Ltd. was put into operation at the 110 thousand volt Huqiao substation in Jiangbei New Area, Nanjing. So far, the device has been operating safely for more than three months, the qualified rate of power supply voltage of Huqiao substation has always been maintained at 100%, the harmonic content has been reduced by 15.6%, and the voltage flicker phenomenon has been fundamentally suppressed.
The supercapacitor micro-energy storage device is multi-functional, which has the advantages of compact structure and small footprint, and can give full play to the efficiency of sporadic idle space resources in the substation. In addition, it can also replace substation capacitors and reactors, covering only 60% of the traditional equipment, and the voltage curve control is smoother, which greatly improves the intelligent level of the substation. The device is composed of supercapacitor energy storage cabinet, PCS, EMS and step-up transformer.
Supercapacitors have the advantages of fast charging and discharging speed, long cycle life and high safety, especially suitable for short-term large-capacity power demand scenarios, and the discharge rate is more than 100 times that of lithium batteries, and has become a new type of energy storage element that has attracted widespread attention at home and abroad in recent years. If supercapacitors can be applied in the power grid, they can quickly release energy and solve the problems of grid frequency instability and voltage sag in the case of large disturbances.
With the commitment of "dual carbon", the large-scale application of power electronic equipment such as wind power and photovoltaic generator sets and DC transmission devices in the power system has significantly shortened the operating time of traditional coal-fired units and reduced the carbon emission level of electricity consumption. However, while replacing traditional coal-fired units, power electronic power generation equipment also reduces the rotating reserve capacity of the power grid. The low inertia and underdamping characteristics of power electronic power system are the biggest challenges facing the safe and stable operation of large power grids.
Energy storage technology can effectively improve the way of rotating reserve capacity of power grid, and the application of supercapacitors in substation grid frequency modulation has attracted great attention from the industry. With the further upgrading of the industrial structure and the increasing proportion of high-end enterprises, supercapacitor micro-energy storage devices can be popularized and applied in substations and distribution stations, bringing broad application prospects for supercapacitor micro-energy storage.