imagine that if every household’s self-provided water well is connected to the urban tap water pipe network, problems such as unstable water pressure, uneven water flow and reverse flow of residual water will inevitably affect the safe operation of the main network. Similarly, the output of distributed photovoltaic power generation is greatly affected by the weather. After a large number of connections, it is easy to cause power grid problems such as voltage fluctuation, frequency oscillation, reverse heavy overload, etc., and even large-scale off-grid risks occur, resulting in clean green power “being generated and not being sent away”. How to make distributed photovoltaic “listen to the order” to promote the stability and orderly integration of green power into the power grid, service users? Jining gives the answer.
not long ago, the national key research and development plan “very high penetration distributed photovoltaic power generation adaptive grid connection and active synchronization key technology” project (hereinafter referred to as “national heavy project”) passed the acceptance of the Ministry of industry and information technology, and the national grid Jining power supply company built the first domestic demonstration project of million kilowatt distributed photovoltaic wide-area collaborative optimization operation, enabling millions of photovoltaic installations to realize second-level “group control”, let the new energy “be well sent, received and used steadily”.
at noon on April 2, the sun shone on the roof of Jining holy land electric power intelligent industrial park, and the 1.5 MW distributed photovoltaic array glowed with silver blue luster, silently converting the sun into green current. On one side of the photovoltaic panel, 15 new inverters buzz slightly, like dutiful “energy guards” guarding the stability of the power grid.
Distributed photovoltaic is different from centralized photovoltaic’s “unified Internet access and unified scheduling”, but “local consumption and nearby consumption”. Wang Yue, Special Officer in Science and Technology Management of the Development Department of Jining Power Supply Company of the State Grid, said that if photovoltaic power generation at noon far exceeds the user’s power demand, the excess power can only be sent back to the large power grid. Once the reverse power transmission is too large and reverse heavy overload occurs, the load rate of transformer or line will exceed the safety threshold.
Jining Holy Land Power Smart Industrial Park 1.5 MW Distributed Photovoltaic.
Faced with this problem, the project team has innovated and developed a new type of photovoltaic inverter with the integration capability of “perception-decision-execution”, which can not only break through the traditional passive response mode, but also support the adaptive switching between “following the network” and “constructing the network. That is to say, once the reverse heavy overload occurs, the grid inverter can not only actively “step on the brake”, but also stabilize the voltage and frequency like “Dinghai Shenzhen”, reduce the power quality decline caused by reverse overload, and improve the efficiency of photovoltaic utilization.
“As a distributed photovoltaic ‘active support’ cluster control demonstration park, Jining Holy Land Power Intelligent Industrial Park adopts 5G LAN communication for the first time in China, realizing full 5G wireless control of distributed photovoltaic clusters.” Staff member Ma Xiangteng said that unlike the “wired connection” of traditional photovoltaic equipment, the 1.5 MW photovoltaic panels in the industrial park realize “millisecond” data transmission through 5G flexible slicing technology, and the group control response period is reduced from the original minute level to less than 150 milliseconds, so that the regulation can keep up with the “face changing speed” of photovoltaic power generation and instantly curb reverse heavy overload.
At present, the installed capacity of distributed photovoltaic in Jining area has reached 3.9308 million kilowatts, with a penetration rate of more than 50%. To make the million kilowatt-level distributed photovoltaic “step by step”, it is inseparable from a powerful “smart brain”.
On the screen of the wide-area distributed photovoltaic collaborative control system located in the power dispatching control center of Jining Power Supply Company of the State Grid, the operation status, power forecast and dispatching instructions of the city’s distributed photovoltaic are clear at a glance. The distributed photovoltaic cluster autonomy technology developed by the National Heavy Project aggregates massive scattered equipment into virtual “super photovoltaic units” and builds a three-level control architecture of “local autonomy-regional mutual aid-wide area coordination”, which promotes the leap from single-point management to large-scale collaborative scheduling of distributed photovoltaic, and the new energy consumption rate increases to more than 98%.
“hundreds of scattered small photovoltaics are packaged into a’ photovoltaic army’ that can work together. unified command and unified action can not only solve the problems of reverse flow overload and voltage fluctuation, but also make photovoltaics available.” State Grid Jining Power Supply Company Regulation Center Director Zhou Ke introduction. Distributed photovoltaics actively participate in peak shaving and frequency modulation, expanding the adjustable resources of the power grid by about 30%, increasing the utilization rate of new energy by about 1 percentage point, and greatly reducing the phenomenon of “abandoning light.
