Monir Hossain

Bio: Monir Hossain is an academic researcher from University of New Orleans. The author has contributed to research in topics: Current transformer & Fault (power engineering). The author has an hindex of 4, co-authored 9 publications receiving 32 citations.

Partial operating current characteristics to discriminate internal and external faults of differential protection zones during CT saturation

Abstract: To protect transformers, transmission lines and busbar systems, low impedance current differential protection schemes based on percentage restraint characteristics are widely used in power systems. The main application issue of these schemes is mis-operation due to current transformer (CT) saturation during close-in external faults. A comprehensive fault discrimination algorithm is highly required for current differential protection schemes to overcome the CT saturation issue. The purpose of this study is to introduce a methodology based on partial operating current (POC) characteristics which discriminate internal and external faults of differential protection zones. The study includes the mathematical model of POC characteristics, a fault discriminating algorithm using POC features, and bus differential protection zone results. The results documented encompasses various possible short-circuit (fault) scenarios and indicate the capability of the proposed algorithm in discriminating internal and external faults under CT saturation conditions.

Revisions on Alpha Plane for Enhanced Sensitivity of Line Differential Protection

Abstract: Line current differential protection based on the traditional alpha plane may block internal faults with outfeed when providing higher security for external faults under current transformer (CT) saturation. This letter proves analytically that the external faults under CT saturation plot away from the negative real-axis of the complex plane and accordingly proposes revisions of the alpha plane characteristics. The modified alpha plane enhances the sensitivity of line current differential protection by unblocking more space along the negative real-axis where internal faults with outfeed are plotted.

Design and testing of a bus differential protection scheme using partial operating current (POC) algorithm

Abstract: This paper presents a novel bus differential protection scheme that provides enhanced immunity against mis-operation resulted from current transformer (CT) saturation during close-in external faults and better sensitivity for internal faults. The proposed scheme incorporates a fault discrimination algorithm based on partial operating current (POC) characteristic making the scheme capable of discriminating high current internal and external faults even with CT saturation. A supervision technique based on CT saturation detection is also included in the scheme design to increase the sensitivity of the proposed relaying scheme for very high impedance internal faults. A relay model is built in Matlab platform based on the proposed scheme and the performance is validated using a transmission network simulated in Electromagnetic Transients Program (EMTP) for various fault scenarios. Documented results show the proposed scheme improves the performance in terms of reliability, sensitivity, and selectivity over traditional bus differential schemes.

Comparative analysis of fault discrimination algorithms on sensitivity to high impedance busbar faults

Abstract: Presently there is not one differential protection characteristic which is self-sufficient to detect all possible busbar faults accurately. Particularly, during close-in external fault, current transformer (CT) saturation creates high operating current which can cause mal-operation of differential relays. As a result, a fault discriminator is necessary to supervise the differential schemes to prevent undesired tripping operation. Most of the existing fault discrimination algorithms have been proven as an efficient external fault detector; however, they suffer from lack of sensitivity to high impedance internal faults. This paper presents a comparative analysis on sensitivity of three existing fault discrimination algorithms including Phase Angle Comparison Algorithm (PACA), Rate of Change of Differential Algorithm (ROCODA), and Alienation Coefficient Algorithm (ACA). Fault simulations were performed using a three-bus test system. The results documented in this paper show that the degree of sensitivity of ROCODA and ACA are similar and much higher than PACA. The comparative analysis presented in this paper can be employed as a useful guideline for selection of an appropriate protection scheme for busbar systems.

A dynamic current allocation algorithm for alienation coefficient based busbar fault discriminator

Abstract: Alienation coefficient based busbar fault discriminator is one of the latest methods used to supervise the busbar differential protection schemes for detecting internal and external faults correctly. This fault discriminator uses alienation coefficient of current signals obtained from equivalent two-terminal busbar configuration to discriminate internal and external faults. This paper reports the impact of dynamic changes in network topology of power systems on the performance of alienation coefficient based fault discriminator. A Dynamic Current Allocation Algorithm (DCAA) is presented for the fault discriminator to address the impact of network topology alteration. The performance of the modified fault discriminator is validated by a simulation study. The results documented in this paper show the capability of modified fault discriminator in discriminating internal and external faults even when there is a dynamic change in network topology.

A multiobjective hybrid bat algorithm for combined economic/emission dispatch

Abstract: In this paper, a multiobjective hybrid bat algorithm is proposed to solve the combined economic/emission dispatch problem with power flow constraints. In the proposed algorithm, an elitist nondominated sorting method and a modified crowding-distance sorting method are introduced to acquire an evenly distributed Pareto Optimal Front. A modified comprehensive learning strategy is used to enhance the learning ability of population. Through this way, each individual can learn not only from all individual best solutions but also from the global best solutions (nondominated solutions). A random black hole model is introduced to ensure that each dimension in current solution can be updated individually with a predefined probability. This is not only meaningful in enhancing the global search ability and accelerating convergence speed, but particularly key to deal with high dimensional systems, especially large-scale power systems. In addition, chaotic map is integrated to increase the diversity of population and avoid premature convergence. Finally, numerical examples on the IEEE 30-bus, 118-bus and 300-bus systems, are provided to demonstrate the superiority of the proposed algorithm.

New Algorithm for Protection of Double Circuit Transmission Lines Using Modal Currents

Abstract: This paper presents a new protection algorithm for double circuit transmission lines using the sum of ratios of modal currents. Relay-operating characteristics is proposed using the complex ratio of modal currents. The proposed algorithm estimates modal domain line parameters and identifies the faulty phases for single pole-tripping applications even during inter-circuit faults. The scheme is sensitive to high resistance internal faults and also detects internal faults with outfeed. The proposed scheme is immune to mutual coupling and is found robust to uncertainties in parameter estimation due to measurement inaccuracies. The scheme is tested for its effectiveness to deal with current transformer saturation and synchronisation error. The scheme protects series compensated double circuit transmission lines even in the presence of current inversion. Exhaustive case studies in electromagnetic transient program (EMTP)/alternate transient program are performed on 400 kV, 300 km, double circuit transmission lines and the proposed protection algorithm is implemented in MATLAB. The results confirm the superiority of the proposed scheme.

A New Principle for Initial Traveling Wave Active Power Differential Busbar Protection

Abstract: To avoid the impact of the transient saturation of a current transformer, a fast busbar protection method based on the initial traveling wave integrated active power differential principle is proposed in this paper. The Peterson equivalent model is applied to analyze the initial traveling wave distribution characteristics of the internal and external faults of the busbar. The initial traveling wave active powers of each sampling point on each transmission line connected to the busbar are calculated with the implementation of an S-transform. By introducing the integrated active power actuating quantity and active power braking quantity, a protection criterion with a characteristic braking ratio is proposed. The theoretical analysis and experimental simulation results show that the protection performance is sensitive and reliable, with a quick response and simple criterion, and is essentially not susceptible to the impacts of the initial fault angle, fault type, and fault resistance.

Enhanced Generalized Alpha Plane for Numerical Differential Protection Applications

Abstract: This paper revisits the generalized alpha plane (GAP) formulation applied to differential protection of multi-terminal apparatus. The GAP formulation is improved by aiming for three main goals: 1) control over the internal fault settlement region (FSR); 2) enabling a simple operation characteristic instead of a restraint characteristic; and, 3) The adjustments are not dependent to the device type. For this purpose, the GAP formulation is redefined in terms of two settings, which transform the FSR into a circumference with a controllable center and radius. Thereby, a circular operation characteristic with an adjustable radius is enabled around the FSR, for to improve security. To validate and test the performance of the improved GAP, numerous computer simulations have been carried out using Alternative Transients Program on different multi-terminal equipment (i.e., busbars, transmission lines, and power transformers). Furthermore, massive data analysis is held as a means to highlight the GAP's sensibility. The obtained results demonstrate a well-stable pre-fault point, a consistent circular FSR, and the effectiveness of the improved GAP even under severe conditions.

Sampled value-based bus zone protection scheme with dq-components

Abstract: This study presents a novel algorithm based on dq-components, which has been effectively used for bus zone protection. The analogue current transformer (CT) secondary signals are acquired and converted into sampled values. Then, the fundamentals of an instantaneous current-based differential protection scheme (87B) have been considered to establish the trip logic of the proposed scheme. Its performance has been validated by simulating faults on an existing 400-kV substation with a double-bus-single-breaker configuration. Moreover, a laboratory test bench has been developed to test the authenticity of the proposed scheme for various fault scenarios. The obtained results from the simulation model and laboratory prototype testify the claims of higher sensitivity during internal faults and better stability during external faults with CT saturation. The proposed scheme has been able to provide high-speed busbar protection against a wide range of internal faults. Comparative evaluation with contemporary busbar protection schemes clearly indicates its superiority.