- Substation energy storage attempts millisecond power grid frequency modulation
- 2019/3/8 Nanjiang Electric (Zhejiang) Co. Ltd.1699
- Recently, the State Grid Co., Ltd. took the lead in releasing the "carbon peak, carbon neutral" action plan. The plan clearly states that it is necessary to strengthen the construction of system regulation capacity, vigorously promote the construction of pumped storage power stations and peaking gas power plants, and promote the application of large-scale energy storage devices. In February this year, the substation supercapacitor micro-energy storage device independently developed by State Grid Jiangsu Electric Power Co., Ltd. was put into operation, which can fast power response, actively suppress grid harmonics, flexibly adjust reactive power, improve power supply reliability, and help the power grid to operate more safely and reliably.
"Since the supercapacitor micro-energy storage device was put into operation, the qualified rate of the power supply voltage of the Huqiao substation has always been maintained at 100%, the harmonic content has been reduced by 15.6%, and the voltage flicker phenomenon has also been fundamentally suppressed." With this device, we no longer have to worry about customer feedback on power quality." Jiangsu Nanjing power supply company deputy director of the inspection department He Ping said. 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 in the 110 kV Huqiao transformer Station in Jiangbei New District, Nanjing. As of March 8, the device has been operating safely for 29 days, and has played an important role in improving the power quality and power supply reliability of Nanjing Jiangbei National Development Zone.
Flexible regulation, new energy storage devices make the power grid more secure
At present, the large-scale application of power electronic equipment such as wind power and photovoltaic generating units and DC transmission devices in the power system has significantly shortened the operation 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 rotation reserve capacity of the grid. The characteristics of low inertia and underdamping of electronic power systems are the biggest challenges to the safe and stable operation of large power grids.
Energy storage technology is currently recognized as an effective way to improve power grid rotation reserve capacity. There are many ways to store energy, including lithium batteries, lead-acid batteries, lead-carbon batteries, etc., based on chemical methods, flywheel energy storage based on mechanical methods, pumped storage based on potential energy, compressed air energy storage, and supercapacitor and superconducting magnetic energy storage based on electromagnetic fields.
Dr. Shi Mingming, senior engineer of Jiangsu Electric Power Research Institute, said that due to the limitation of electrochemical reaction rate, the power density of electrochemical energy storage systems such as lithium batteries, lead-acid batteries, and lead-carbon batteries is relatively small. When transient disturbance event power abrupt change occurs, the electrochemical energy storage system can not quickly absorb or release the target power, it is difficult to meet the dynamic requirements of the system.
Supercapacitors have the advantages of fast charge and discharge speed, long cycle life and high safety, especially suitable for short-time large-capacity power demand scenarios, discharge rate is more than 100 times that of lithium batteries, and in recent years, it has become a new type of energy storage components that have been widely concerned at home and abroad. If the supercapacitor can be applied in the power grid, it can quickly release energy and solve the problems of frequency instability and voltage sag in the case of large disturbance.
Based on the performance advantages of supercapacitors, in August 2019, the Jiangsu Power Equipment Department of State Grid set up a special technical research team to improve power quality, focusing on "jam neck" problems such as voltage sag and harmonic elimination. Jiangsu Institute of Electrical Science and Technology professionals in-depth field research, analysis and comparison of technical routes, put forward a set of harmonic suppression, reactive power compensation, temporary drop management, energy storage and other functions in one of the supercapacitor micro-energy storage technology scheme.
In order to ensure the feasibility of the project, the research team first completed the functional tests of the 50kW prototype in the laboratory, and then carried out the development of the 500kW supercapacitor micro-energy storage device. The device is mainly composed of three parts: supercapacitor module, power electronic converter and fast power controller. The fast power controller can complete the frequency detection within 10 milliseconds, and the power electronic converter can realize the fast and accurate support of the active power within 2 milliseconds, and the power electronic converter integrates the active suppression of harmonic waves in the power grid and the flexible adjustment of reactive power, making the device a new compensation device integrating energy storage and power quality management. On February 7 this year, the substation supercapacitor micro-energy storage device was put into use.
Pilot first, millisecond response makes the grid more reliable
"Jiangsu, as a key town in the Yangtze River Delta, has developed high-end manufacturing, numerous high-tech industrial parks, and high output value users such as semiconductor integrated circuit enterprises and data centers have high requirements for power quality." How to further improve power quality has become an urgent problem." State grid Jiangsu power equipment department deputy director Jing Weiwei said.
He introduced that Nanjing Jiangbei New Area, as the only state-level new area in Jiangsu Province, is an important support point for Jiangsu to connect with the "Belt and Road" Initiative and the Yangtze River Economic Belt strategy, with fast growth of electricity load and high requirements for power supply reliability. The 110 kV Huqiao substation is near the Yangtze River and near the Nanjing Science and Technology Innovation Headquarters building, and its main power supply customers are large office buildings, high-tech research and innovation parks, free trade zones, etc., which has particularly high requirements for power supply reliability.
"Since the supercapacitor micro-energy storage device was put into operation in the 110 kV Huqiao Substation in Jiangbei New Area, it has detected the power grid operation data in real time, dynamically adjusted the reactive power of the power grid, eliminated the harmonic current exceeding the standard of the power grid, compensated for the voltage dip of the power grid, and ensured the quality of power supply. With this support, the grid is more secure." Shi Mingming said. He introduced that under normal circumstances, the device operates in a comprehensive power quality management mode to ensure the quality of daily power supply. In case of a frequency drop caused by a large fluctuation in the power grid, the micro-energy storage device can enter an frequency modulation mode within 12 milliseconds. Because of the large mechanical inertia of the traditional generator set, the response delay of a frequency modulation will reach more than 10 seconds, resulting in the expansion of the fault range. The supercapacitor micro-energy storage device is like a "turbocharger device", which makes up for the power gap in the key time window and significantly speeds up the primary frequency modulation process of the power grid.
The future is broad, and small devices have great potential
By the end of 2020, the installed capacity of new energy power generation in Jiangsu power Grid has reached 32.177 million kilowatts, accounting for 22.7% of the total installed capacity of power generation in the province. According to the State Grid Jiangsu Power "14th Five-Year" plan, the proportion of new energy power generation installed capacity of Jiangsu power grid will be further increased - by the end of 2025, the total installed capacity of wind power in Jiangsu will reach 52 million kilowatts, and the total installed capacity of photovoltaic power generation will reach 38 million kilowatts, which will account for nearly 50% of the total installed capacity of the province. The high proportion of new energy access is bringing new problems to the existing grid, and the grid urgently needs millisecond fast power support devices.
Jiangsu Power Grid has been exploring the development and application of energy storage technology to improve the safe operation level of the power grid. In recent years, State Grid Jiangsu Electric Power has built a large-scale interactive system of source, grid and load, and has successively put into operation electrochemical energy storage power stations in Zhenjiang, Suzhou, Huaian and other places, with a total capacity of 220,000 kilowatts. Electrochemical energy storage has outstanding advantages in eliminating new energy fluctuations, reducing load peak-valley difference, improving the utilization rate of power supply equipment, and improving the reliability of power supply, and is an important means to achieve clean energy supply, intelligent user electricity consumption, and efficient interaction of network load. The successful operation of the 110 kV Huqiao Substation supercapacitor energy storage demonstration project in Jiangbei New District of Nanjing has explored a new way for the application of safe, economical and efficient energy storage technology.
The supercapacitor micro-energy storage device has the advantages of compact structure and small footprint, and can give full play to the efficiency of scattered idle space resources in the substation. In addition, it can also replace substation capacitors and reactors, occupy only 60% of the traditional equipment, and the voltage curve control is smoother, which greatly improves the intelligent level of the substation.
"The supercapacitor micro-energy storage device can not only be used as a 'turbocharging device' of the power grid to ensure the safe and stable operation of the power grid; It is also the power grid harmonic cleaner, which can ensure the green power supply of users; It is also the 'charging treasure' of the distribution network, which can ensure uninterrupted power supply for users when the voltage dips suddenly." State grid Jiangsu power equipment management Department technology deputy director Fu Hui said.
With the further upgrading of Jiangsu's industrial structure and the continuous increase of the proportion of high-cutting-edge enterprises, supercapacitor micro-energy storage devices will have a good application market. The supercapacitor micro-energy storage device can be popularized and applied in substations and distribution stations in the province. According to the preliminary calculation of Jiangsu Electric Power of State Grid, the available space of substations in the province has the potential to add 2 million kilowatts of supercapacitor micro-energy storage installed capacity, which brings broad application prospects for supercapacitor micro-energy storage. - Industry 4.0 from automatic production to intelligent manufacturing"Fourteen Five" energy transformation speed up the pace of distribution network how to develop high-quality
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