A Time Domain Model Recognition Pilot Protection Method Applicable to Wind Power System

Abstract

The invention discloses a time-domain model identification longitudinal protection method suitable for wind power systems, which includes the following steps: collecting the three-phase voltage and current at the protection installation place to form differential voltage and differential current, and judging whether the differential current value is Start the time domain model to identify the longitudinal protection, calculate the correlation coefficient ρ of the differential current of each phase and the first-order derivative of the differential voltage after zero-sequence compensation, and compare the value of the correlation coefficient ρ of each phase with the set threshold to determine whether the area, External fault; if any phase correlation coefficient ρ is less than the set threshold, it is judged as an internal fault, the longitudinal protection at both ends of the line operates, and the protection device operates reliably; otherwise, it is judged as an external fault, and the protective device does not operate reliably. The invention has the advantages of simple implementation, phase-separated discrimination, fast action speed, and is not affected by distributed capacitance current and fault resistance of lines, and can be widely used in wind power systems.

Description

technical field [0001] The invention relates to the field of new energy grid-connected relay protection, in particular to a time-domain model identification longitudinal protection method suitable for wind power systems. Background technique [0002] With the increasingly serious energy crisis and environmental pollution, the development and utilization of green energy has been paid more and more attention. Large-scale development of various renewable energy represented by wind energy and solar energy has become an inevitable choice for human society to achieve long-term sustainable development. . However, with the large-capacity random fluctuating new energy power connected to the grid, it will definitely have a greater impact on the power system, and at the same time bring a series of technical problems to the operation of the system. [0003] At present, there is a lack of operation experience of large-scale random energy access to the transmission and distribution netwo...

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Problems solved by technology

[0005] Fault characteristics such as weak feed, high harmonics, frequency offset, and system impedance instability of the wind power system have caused the unsuitability of traditional relay protection, resulting in the requirements for relay protection of wind power systems that are different from conventional system fault characteristics. In addition, The model of faults inside and outside the zone is different from the traditional relay protection. Therefore, a longitudinal protection method that can be applied to wind power systems is needed

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