| In the 21 st century, environmental pollution, energy crisis and other issues have become a "bottleneck" that restricts the economic development of various countries. The development and utilization of clean energy has risen for our country's national energy strategy. The area of research in this paper, an important energy base of its province and even our whole country, is rich in solar and wind energy resources and is the main battlefield of the development and utilization of clean energy. The surplus electricity in this area is mainly transmitted to its southern region for consumption, but the power transmission capacity is restricted by the transmission section, "750k V TB7-TB8 double-circuit transmission line +330k V TB28-TB29 transmission line +330k V TB28-TB30 transmission line". With the sharp increasing of installed capacity in this area, the research of the ultimate transmission capacity(UTC) of the receiving section of this area, which can improve the power delivery capability of this area, becomes imperative.Power delivery capability of transmission section is defined as Available Transmission Capacity(ATC) of the grid under various constraints. The premise of calculating ATC is the searching of transmission section. After transmission section determined, the deterministic or probabilistic methods can be used to calculate the ATC of the section. In order to obtain the main steady state constraint conditions of the outward power transmission capability, the detailed concepts and calculation methods of the transmission section of its transient stability limit, thermal stability limit and static stability limit were given, and the influences of the three kinds of stability constraints on transmission section were analyzed. Then the transmission power of the section M under its transient, static and thermal stability limit was calculated qualitatively on New England 39 nodes standard system. The binding effects of three stable constraints on the UTC of the section were compared and the conclusion that the UTC is mainly limited by transient stability constraints was obtained.Since transmission section between the power of this area and power grid of its southern region is relatively weak and forms a high and low voltage ring network, the transmission capacity of the main section is restricted by transient stability. In this paper, The Power System Analysis Software Package was used to calculate the stability-limit of the area electric power transmission section and receiving section in a variety of operation modes by its power flow calculation and transient stability analysis modules. By calculating, it was obtained that the stability-limit capacity of the transmission section of this area was maintained at about 1200 MW before the GB1 and GB2 power plant put into, while the stability-limit capacity of the receiving section will increase to 2100 MW after the GB1 and GB2 power plant put into. The obtain of the stability-limit capacity of receiving section of this power grid,which can be a reference for the grid operation scheduling personnel to ensure safe and stable operation of the section.To further enhance the ability of Outward Power Transmission Capability of the power of this area, this article took account of the power access scheme and delivery strategy from the perspective of connecting power sources and power grid planning. Firstly, according to a recent power planning, especially the network planning of wind power generation, the recent electricity access programs and sending strategies were designed. Then considering by the end of 2017, generating capacity will add 3940 MW in this area with respect to the end of 2015. In order to promote this part of the power-consumption, the long-term electricity access and delivery strategy were proposed in this area. Finally, from the perspective of the electricity market, a number of strategies and suggestions to protect the power delivery of this area were proposed. |
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