Pole-to-Ground Fault Analysis and Fast Protection Scheme for HVDC Based on Overhead Transmission Lines

Abstract

Flexible direct current (DC) transmission network technology is an effective method for large capacity clean energy access to power grids, but the DC short-circuit fault detection for it is a difficult problem. In this paper, the pole-to-ground fault transient characteristics in a multi-terminal DC power grid, based on overhead transmission lines and DC circuit breakers, are analyzed firstly. Then, a fast protection scheme is proposed according to the fault transient characteristics. Only local information is utilized for fault detection and location in the proposed scheme. Moreover, the scheme is verified to have the advantages of fast action speed, high reliability and the ability to resist the transition resistance. A four terminal DC power grid model based on actual engineering parameters is established in PSCAD/EMTDC, and the validity of the protection scheme under different fault conditions is verified by simulation results.

Enhanced Fault Current-Limiting Circuit Design for a DC Fault in a Modular Multilevel Converter-Based High-Voltage Direct Current System

“…Constraint (43) can be analyzed using the arm current Equations (24) and (25) in Section 2. Setting R FCL = 20 Ω, the L FCL_min is calculated as 219 mH to satisfy Constraint (43). The arm currents are compared under the calculated L FCL_min and L FCL_min obtained via a simulation ( Table 3).…”

“…Considering that the resistance value of a 2 mH reactor equals 18.9 mΩ [42], the power loss is expressed as Equation (49). where is the rated DC line current, = 0.00945 Ω/mH is based on Reference [43], is the smoothing reactor, and is the rated DC line power. Thus, the smoothing reactor in the proposed scheme causes 0.135% power loss in comparison with the rated DC line power, thus denoting a promising economic efficiency.…”

“…In order to cooperate with protection relaying, the proposed FCL circuit is installed at the ends of transmission line so that communication delay among DCCB, measure point and protection relay could be reduced. Moreover, big smoothing reactor (200 mH) in [42][43][44] would influence the dynamic response speed and proposed FCL circuit could help reduce value of smoothing reactor for better performance of dynamic response. However, it requires further investigation on economic efficiency of proposed method, considering previous FCL methods, such as superconductor based fault current limiter, FCL circuit and converter topology based approach.…”

Study on the Hazard Limitation of Hybrid Circuit Breaker Actuator Operation

“…The article concerns the analysis of processes and the operation of hybrid switches [1,2] related to the arcless switching off of short-circuit currents in power circuits operating in difficult environmental conditions [3,4]. In the conditions under consideration, the main cause of disruption of the power system operation is a dynamic short circuit, but one cannot omit such factors as vibrations, lightning, or changing weather conditions.…”

Asynchronous Fault Location in Transmission Lines Considering Accurate Variation of the Ground-Mode Traveling Wave Velocity

“…The traditional fault location is based on the line protection action. Numerous methods have been proposed for transmission line protection [1], with no consideration of the exact fault location, causing the need for time-consuming line patrols. It is necessary to find the exact fault location in transmission lines.…”