Обґрунтування побудови резервних централізованих захистів ліній електропередач високої напруги

Анотація

BACKGROUND OF CONSTRUCTION OF BACKUP CENTRALIZED POWER PROTECTION HIGH VOLTAGE

V. Ia. Bunko

The attention is focused on the principles of building a centralized relay protection devices, which are given structural expression triggering conditions, discusses their pros and cons. Presented centralized backup protection algorithm (directional overcurrent protection with advanced logical part of the centralized protection schemes four- and hexagon), based on the known principle, in which the short circuit is determined by the direction of the power in the relevant branch of the circuit and is located next disconnecting switches. The role of the algebra of logic and reliability in their construction.

Among the traditional centralized greatest interest is the differential current busbar protection, since it is based on the analysis of only the feeder currents and applying Kirchhoff's first law without the use of sending power information. The evaluation of existing developments in centralized backup protection, the urgency of creating a new set targets.

The proposed principle of the centralized backup protection from short circuits to ground transmission lines 330-750 kV ring circuits outdoor switchgear, in contrast to the known, based on monitoring phase currents relations on the side of low voltage step-up transformer power supply. Developed algorithms of functioning, methods of selecting the settings, evaluation of sensitivity, considering the currents in the healthy phases and security model.

By controlling the amounts of currents connections intact and current values in injured, the proposed method of construction of the centralized protection against phase faults, based on the use of the first law of Kirchhoff.

The developed algorithms centralized backup protection from the mentioned connections interphase fault comparison power sign on them. These differ from the known algorithms taking into account the significantly larger number of operating modes of the equipment. Among the most traditional centralized іnteres causes a differential current busbar protection, since it is based on the analysis of only the current connections and the application of the first law of Kirchhoff without the use of sending power information.

Evaluation of the sensitivity of traditional backup protection from phase faults (overcurrent and distance protection) and on the single-phase ground fault (zero sequence).

To solve the problems in the thesis used the fundamental provisions of the theoretical foundations of electrical engineering, relay protection, reliability theory, electrical machines, the algebra of logic and the theory of relay devices. Perform mathematical modeling, all calculations are made in MS Excel environment, Mathematica 5,0.

The developed algorithms, through the use of algebra of logic may be implemented in the microprocessor terminals and logical elements of any nature. They allow you to back up the protection of outdoor switchgear 330-750kV voltage of phase faults, suitable for use in majorization. Adapting to unbalance and change the main circuit, as well as algorithms serviceability control, increase the reliability of the failure protection, which is especially important when they are performed by a microprocessor. Protection based on the use of the first Kirchhoff's law, as opposed to applied, does not respond to damage in voltage circuits, which increases the reliability of the whole system during relaying majorization.