Shijiazhuang, Hebei Province built a 500 kV ring network

On June 22, news came from the State Grid Hebei Electric Power Company that the 500 kV Guiyuan double-loop line of Hebei South Grid was successfully put into operation a few days ago, which marked the completion of the 500 kV ring network in Shijiazhuang, basically eliminating the risk
of more than 20% of the power grid major accidents (three-level power grid incidents) in provincial capital cities that may be caused by the failure of the 500 kV Lianbei double line.

The 500 kV Guiyuan double line is the backbone line of the power grid in southern Hebei and the key link
in the formation of the 500 kV ring network in Shijiazhuang.
Due to the long-term heavy-load operation of the 500 kV Lianbei double line, the power flow of the normal operation of the single-loop line is close to 1.
5 million kilowatts, if a double-loop line fault occurs, it will cause a serious overload of the 220 kV Beifang line and Changdong I.
line, and it is necessary to limit the power of 1 million kilowatts in the central and southern parts of Shijiazhuang, and the load outage ratio exceeds 20% of the load of Shijiazhuang power grid, which will cause a three-level power grid incident
.
To this end, State Grid Hebei Electric Power accelerated the construction of 500 kV Guiyuan double-loop line, promoted the formation of a 500 kV ring network in Shijiazhuang area, and actively eliminated hidden risks
in the power grid.

The construction of 500 kV Guiyuan double line spans 9 lines of 220 kV and above in Shijiazhuang power grid
.
Among them, during the period of crossing the 500 kVA double line, 4 units and 1.
8 million kW units of Shang'an Power Plant need to cooperate with the shutdown, and the power outage arrangement is subject to the construction of the Mengxi-Tianjin South UHV line
.
The rest of the power outage will also cause 2 220 kV substations in Shijiazhuang Power Grid to supply power for 31 days and two 220 kV stations to be blacked out for 15 days, and the power grid operation risk is greater
.

In order to ensure the progress of project construction and the safety of power grid operation during the construction transition, State Grid Hebei Electric Power fully applies the results of 2~3 years of rolling analysis and verification of the power grid, scientifically formulates technical plans and milestone plans, optimizes power outage construction plans, and strictly controls power grid operation risks
.
On the basis of fully considering the operation structure of the power grid and the needs of on-site construction, the 500 kVA double-line power outage was arranged to carry out the construction leap by taking advantage of the load trough period of the Spring Festival, so as to minimize the impact
on the power balance.
At the same time, the company strengthened the control of the whole process of the project, repeatedly optimized the construction plan, and made every effort to ensure the progress
of the project implementation.

During the construction of the project, State Grid Hebei Electric Power strengthened the early warning and pre-control of operational risks by implementing an enterprise-level risk prevention and control mechanism, minimizing the impact on the power balance and reducing the risk of
equipment overload 。 Carefully study the operation mode of the power grid during the power outage transition period, take the large load of spring irrigation peak and the serious failure of N-2 as the calculation basis, strengthen the analysis and verification of power grid security, issue risk early warning in advance, issue a total of main network risk early warning documents, compile more than 10 main network safety measures, carry out special anti-accident drills 4 times, ensure that the 500 kV Guiyuan double-loop line is put into operation as planned, and eliminate the power grid operation risk
in southern Hebei in time before the arrival of the summer load peak.

The formation of 500 kV ring network in Shijiazhuang area enhances the power transfer capacity of the regional 500 kV power grid, effectively alleviates the problem of high transmission pressure of lines in Shijiazhuang area, and at the same time improves the reliability and flexibility of 500 kV power grid operation and 500 kV Yuanshi substation regulation, reduces the impact of 500 kV line failure on the 220 kV power grid, provides conditions for the 220 kV power grid to realize regional power supply in the region, and greatly improves the safety and flexibility of power grid operation
。