| Due to the rich water resources in our country, the development of hydro-generator can improve energy production and provide protection for the rapid economic development. With the increasing of installed capacity of hydro-generator and the intensifying of the interconnection of electrified wire netting, the mutual influence between hydro-generators and power grids has become the one of the most critical technical problems that affects the safety of power system. Strengthening the research on coordination between hydro-generators’protections related to grid and network, which is beneficial for the safety of power system and plants, is the base of building up the strong smart grid.Firstly, hydro-generator’s loss-of-field and out-of-step protection model is build up to study the dynamic response characteristics of these two kinds of faults and the performance of traditional criterions is tested based on the model. Secondly, the traditional loss-of-field criterion depends on delay unit to avoid the influence of power swing, which makes the action slowly. To solve the problem, a new loss-of-field protection criterion based on the impedance circle of oscillation boundary criterion is proposed. Finally, this paper proposes a suitable scheme of the coordinative setting calculation to solve the problem that the current coordinative. setting calculation between the minimum-excitation limitation and the loss-of-field protection is inaccurate. Using the proposed scheme, generators can give full play to ensure the safety of power system in different kinds of conditions. |
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