Zhejiang Electric Power actively builds a new power system dispatching system

China Energy Storage Network News: Recently, State Grid Zhejiang Electric Power Co., Ltd. held an on-site meeting in Ningbo to discuss the construction of a new generation of dispatching technology support systems at the municipal level to study the subsequent construction plans for dispatching technology systems in various cities across the province.

With the advancement of various work in Zhejiang Electric Power Construction's State Grid's new power system provincial demonstration zone, the power grid's safety foundation and operating mechanism are changing synchronously. As the nerve center for the safe and stable operation of the power grid, the grid dispatching is also constantly upgrading and optimizing to adapt to the construction of the new power system.

Traditional power dispatching system faces challenges

The rapid growth of new energy installed capacity has brought an impact on the balance of traditional electricity. Data shows that in 2021, Zhejiang's new energy installed capacity reached 24.98 million kilowatts, and the installed capacity accounted for an increase of 28.6 percentage points year-on-year, becoming the second largest power source in Zhejiang Province. The proportion of new energy in terminal energy consumption is about 36%, which is 9 percentage points higher than the national average.

The traditional dispatching method is that the dispatching control center takes into account the power balance work in accordance with the medium- and long-term plans such as the framework agreement between local governments, the annual and monthly power purchase plans, and the real-time operation of the power system, in accordance with the principles of unified dispatching and hierarchical management. However, with the continuous influx of new energy, the power system has taken on new forms and new features. The capacity of new energy units is small, and the number of objects controlled by the power grid has increased sharply to tens of thousands, resulting in the continuous increase in the difficulty of controlling the traditional power system. Therefore, it is necessary to improve the automation capability of power dispatching.

In general, the traditional power dispatching system cannot fully adapt to the efficient operation of the new power system, and there is still room for improvement in terms of safety, stability, balance and security.

At present, the UHV grid of Zhejiang Power Grid is a "two AC and two DC" structure. With the advancement of key projects such as Baihetan-Zhejiang UHV, it is expected that Zhejiang will build a "one ring and four DC" UHV hybrid structure by the end of the 14th Five-Year Plan. Such a complex grid architecture has changed the internal characteristics of the power system, requiring the update of secondary equipment such as power system control and protection, and upgrading of the grid dispatching system.

The high proportion of external power has also further promoted Zhejiang to build a new power system dispatching system. In 2021, the maximum external power of Zhejiang power grid has reached 35.78 million kilowatts, and the highest proportion of unified dispatching caliber has reached 44.8%. The high proportion of external power has reduced the composition of various power sources in the province and the number of operating units, thus forming a normal situation of "large power receiving and small start-up", which has affected the safety and stability of the power grid.

In terms of power composition, thermal power is still the largest power source in Zhejiang Province's installed power structure, but its share is decreasing year by year. It is expected that clean energy will become Zhejiang's largest power source by the end of the 14th Five-Year Plan, and the installed power structure will undergo a huge change.

Actively explore new power dispatching system

Zhejiang Electric Power is accelerating the transformation of the grid dispatching and control methods, shifting from emphasizing the dispatching of the main grid to the coordinated dispatching of the entire grid. On the power supply side, it actively serves the optimization of the supply-side structure, optimizes the grid connection and commissioning process of new energy units, and truly achieves "all that should be connected should be connected", and increases the proportion of clean power and zero-carbon electricity. On the grid side, the grid operation efficiency is further improved through virtual power plant aggregation, flexible power flow control, main and distribution network reactive coordination, and optimal power flow optimization. On the load side, the pilot provides auxiliary services through interruptible loads and load aggregators, actively participates in grid regulation interactions, and promotes the overall carbon efficiency of the power system. On the energy storage side, it actively promotes energy storage on the three sides of power supply, grid, and user, and carries out work on energy storage participating in the power auxiliary service market.

In order to accurately understand the "temperament" of renewable energy power generation, Zhejiang Electric Power has also developed a new generation of renewable energy power prediction system, which uses differentiated prediction technologies such as meteorological prediction and grid prediction for both centralized and distributed renewable energy types to further improve the prediction accuracy of Zhejiang's renewable energy. At present, the average monthly forecast accuracy of Zhejiang's wind power is 90.99%, and the average monthly forecast accuracy of photovoltaic power is 94.28%, which is much higher than the industry's 80% forecast standard. At the same time, Zhejiang Electric Power has also promoted the accuracy of social load forecasting, carried out the evaluation of Zhejiang Province's new energy credible capacity, and further calculated the power balance account.

As the first pilot unit in the State Grid Corporation system to undertake "two new generations and one 5G demonstration", Zhejiang Electric Power has continuously applied new digital intelligent technologies to the operation of the power grid, and made every effort to build a new brand project of the brain of intelligent dispatching and operation of the power system. At present, the company has completed the pilot work of the new generation dispatching technology support system in the Zhejiang Electric Power Dispatching and Control Center and the State Grid Ningbo Power Supply Company Dispatching and Control Center, and is the first in the State Grid Corporation system to complete 13 security and reliability function tests of 5G live network slices.

In addition, Zhejiang Power has pushed the government to issue the "Zhejiang Power Spot Market Trading Rules" around new market-oriented transaction requirements such as deepening electricity price reform and power grid companies' agency power purchases, introduced energy storage, pumped storage and other entities to participate in the market, enriched the variety of auxiliary services, and ensured stable market operation.