A novel directional element for transmission line connecting inverter-interfaced renewable energy power plant. (February 2023)

• Record Type: Journal Article
• Authors: Wang, Yuxi; Wen, Minghao; Chen, Yu
• Is Part Of: International journal of electrical power & energy systems. Volume 145(2023)
• Publication Date: 2023-02
• Subjects: Distance protection -- Directional element -- Fault current analysis -- Inverter-interfaced renewable energy source -- Transmission line; Electrical engineering -- Periodicals; Electric power systems -- Periodicals; Électrotechnique -- Périodiques; Réseaux électriques (Énergie) -- Périodiques; Electric power systems; Electrical engineering; Periodicals; 621.3
• DOI: 10.1016/j.ijepes.2022.108682
• Languages: English
• ISSNs: 0142-0615

Abstract

Highlights: Fault transient current of inverter-interfaced source is analyzed in dq -frame. Fault transient current of traditional AC power grid is analyzed in dq -frame. A new time-domain directional element is proposed to cope with zero-voltage fault. Insensitive to variety of impedance and output power of inverter-interfaced source. Fault direction can be determined in short time window with low sampling frequency. Abstract: The fault currents characteristics of inverter-interfaced renewable energy sources (IIRESs) such as direct-drive permanent magnetic synchronous generator and photovoltaic mainly include weak feed, the variety of source impedance and frequency deviation, which may lead to the false operation of distance protection for transmission line connecting inverter-interfaced renewable energy power plant (IIREPP). The R-L differential equation algorithm based time-domain distance protection is not affected by the fault characteristics of IIRES, but it is difficult to determine the fault direction when faults near the relay. In this paper, a directional element suitable for transmission line connecting IIREPP is proposed, and an improved time-domain distance protection composed of the directional element and the R-L differential equation algorithm based time-domain distance protection is proposed. The characteristics of fault currents of IIRES and traditional AC power grid are analyzed and summarized by deriving the analytical expressions of their fault currents in dq synchronous reference frame. The analysis results show that when the back of the relay is the IIRES and the AC power grid respectively, the change trends of the d -axis component of their fault currents are the same in a short time after faults occur in front of the relay, and the changes of q -axis component of their fault currents are obviously different. The directional element is proposed based on the characteristics of the fault currents on both sides of the transmission line connecting IIREPP. The simulation results verify effectiveness of the proposed protection scheme.