Power systems
Mohammadreza Noori; Seyed Ghodratollah Seifossadat; Alireza Safarian
Abstract
In this paper, a novel selective DC fault detector approach based on the adaptive cumulative sum method (ACUSUM) is suggested for the protection of high voltage direct current (HVDC) transmission lines. Using a communication channel, the proposed method detects DC fault occurrence as well as determining ...
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In this paper, a novel selective DC fault detector approach based on the adaptive cumulative sum method (ACUSUM) is suggested for the protection of high voltage direct current (HVDC) transmission lines. Using a communication channel, the proposed method detects DC fault occurrence as well as determining faulty line at a multi-terminal HVDC (MT-HVDC) transmission system; the whole in less than 2ms. The suggested approach works in the time domain and employs the ACUSUM method as a mathematical tool for detecting abrupt variation at the magnitude of lines current for fault detection. Simulation results confirm the selectivity of the proposed algorithm at different DC fault situations which enhances the reliability of the power system. Besides the low sampling rate, the ACUSUM calculation burden is very low and its implementation needs no special or complicated hardware. Rather than appropriate speed, adaptivity, independence from system parameters, robustness against fault resistance, fault distance and noise are significant advantages of the proposed algorithm in comparison with other methods. adaptivity, independency from system parameters, robustness against fault resistance, fault distance and noise are significant advantages of the proposed algorithm in comparison with other methods.
Power systems
Mahyar Abasi; Mahmood Joorabian; Alireza Saffarian; Seyyed Ghodratollah Seifossadat
Abstract
Generalized Unified Power Flow Controller (GUPFC) is a member of the flexible alternating current transmission system (FACTS) devices family that operates based on voltage source converter (VSC) and is known as the most efficient FACTs device. GUPFC can control the voltage of one bus and the active and ...
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Generalized Unified Power Flow Controller (GUPFC) is a member of the flexible alternating current transmission system (FACTS) devices family that operates based on voltage source converter (VSC) and is known as the most efficient FACTs device. GUPFC can control the voltage of one bus and the active and reactive power flows on at least two transmission lines with equal voltage levels. This paper presents the mathematical modeling of power injection by GUPFC for the first time. Besides, the accurate design and details of the control system for series and shunt converters of a GUPFC, along with a new mathematical function for pulse generation based on a 48-pulse VSC when the GUPFC is placed in the middle point of a parallel transmission line, are presented in this study. The power injection modeling introduced in this paper is very useful and efficient in Newton-Raphson power flow studies and in modeling different parts of the control system and power electronics converter in dynamic and transient studies. The modeling is implemented in MATLAB/Simulink for a 400 km, 230 kV, and 60 Hz nominal frequency double-circuit transmission line. The satisfactory results provided in the simulations section of the paper verify the validity and accurate performance of the proposed model.
