Keywords
IIDG; AC line; distance protection; fault characteristic
Abstract
The strong variability, spatiotemporal randomness, and nonlinear controlled characteristics during faults of inverter-interfaced distributed generators (IIDGs) such as direct-drive wind turbines and photovoltaic generators pose significant challenges to the existing relay protection systems in power grids. When faults occur in high-voltage lines of substations with integration of IIDGs, the fault characteristics are more complex compared to those in the case of the access of traditional synchronous machine sources to high-voltage lines, which makes it difficult for conventional positive-sequence voltage-polarized phase-comparison distance protection to adapt to. As a result, the performance of protection for power grids deteriorates. This paper analyzes the reasons for the incorrect operation of traditional positive-sequence voltage-polarized phase-comparison distance protection due to the fault characteristics of IIDGs. Based on the electrical quantity characteristics at the protection installation point, it proposes a new method for distance protection of high-voltage lines by using power frequency phasor calculation. When the fault voltage at the protection installation point is relatively high, using the voltage at the protection installation point as the polarizing voltage for phase-comparison distance protection correctly determines the fault distance. For the low fault voltage at the protection installation point, the fault direction is determined by analyzing the phase relationship between the memory voltage at the protection installation point and the current flowing through the point. Simulation results show that the proposed distance protection method exhibits excellent performance unaffected by factors such as fault location and fault type. The proposed distance protection method is applicable to AC line protection for power grids with the integration of IIDGs, and it eliminates the issue of blind zones of protection for outlet faults.
DOI
10.19781/j.issn.1673-9140.2025.02.007
First Page
59
Last Page
67
Recommended Citation
LU, Zhengfei; WEN, Minghao; ZHOU, Yu; JIN, Longxing; and MA, Shuai
(2025)
"A novel distance protection method for high‑voltage line in substation with integration of inverter‑interfaced distributed generator,"
Journal of Electric Power Science and Technology: Vol. 40:
Iss.
2, Article 7.
DOI: 10.19781/j.issn.1673-9140.2025.02.007
Available at:
https://jepst.researchcommons.org/journal/vol40/iss2/7