Manas Kumar Jena

A New Wide-Area Backup Protection Scheme for Series-Compensated Transmission System

This paper presents a new wide-area backup protection scheme based on the phase angle of positive-sequence integrated impedance (PAPSII). The proposed scheme uses phasor measurement units (PMUs) that comply with standard C37.118.1-2011 for retrieving the phasor information. The PMUs provide the positive-sequence phasor information of the voltage and current signals at each and every bus of a system to a phasor data concentrator (PDC). The positive-sequence integrated impedance of each line of the system is extracted, and the PAPSII of each line is continuously monitored at the PDC. The values of the PAPSII help in identifying the faulted line of the power transmission system. The proposed scheme is extensively tested for different types of fault scenarios on a three-machine nine-bus power transmission network on a real-time digital simulator platform. Critical issues such as voltage inversion, current inversion, load encroachment, and the power swing are addressed in the proposed scheme. The test results indicate that the proposed scheme can overcome the limitations of existing backup protection schemes and can provide a reliable protection measure.

Data-Mining-Based Intelligent Differential Relaying for Transmission Lines Including UPFC and Wind Farms

This paper presents a data-mining-based intelligent differential relaying scheme for transmission lines, including flexible ac transmission system device, such as unified power flow controller (UPFC) and wind farms. Initially, the current and voltage signals are processed through extended Kalman filter phasor measurement unit for phasor estimation, and 21 potential features are computed at both ends of the line. Once the features are extracted at both ends, the corresponding differential features are derived. These differential features are fed to a data-mining model known as decision tree (DT) to provide the final relaying decision. The proposed technique has been extensively tested for single-circuit transmission line, including UPFC and wind farms with in-feed, double-circuit line with UPFC on one line and wind farm as one of the substations with wide variations in operating parameters. The test results obtained from simulation as well as in real-time digital simulator testing indicate that the DT-based intelligent differential relaying scheme is highly reliable and accurate with a response time of 2.25 cycles from the fault inception.

Intelligent relaying of UPFC based transmission lines using decision tree

The paper presents an intelligent relaying scheme for transmission line in presence of UPFC. Transmission line distance relaying in presence of FACTs devices like UPFC has been a very challenging task. A new differential feature based approach using DFT based pre-processor and Decision tree (DT) is presented here for protection of transmission lines containing UPFC. A case study considering a 500-kV Transmission line of length 400-k.m(both single circuit and double circuit) is taken for simulation purpose in MATLAB environment and the results obtained show feasibility of the proposed relaying scheme.

Supervisory control based wide area back-up protection scheme for power transmission network

Recent blackouts have induced a sense of urgency among protection engineers to revisit the concept of zone-3 protection in power transmission network. Zone-3 mal-operation is reported to be one of the primary causes behind most of the cascaded outages. The main purpose of this paper is to present a supervisory control based wide area back-up protection scheme. A data-mining algorithm, known as decision trees, is used to classify the state of power transmission system. Further, phase angle of positive sequence integrated impedance is utilised to assist the existing zone-3 protection in order to avoid unnecessary tripping during stressed power system condition. The studies performed on western system coordinating council (WSCC)-9-bus system in Real Time Digital Simulator platform validate the proposed algorithm under various faults and stressed conditions.

A New Decentralized Approach to Wide-Area Back-Up Protection of Transmission Lines

This paper presents a decentralized-approach-based wide-area back-up protection scheme to identify the faulted line in a power transmission network. The proposed scheme divides the whole power system under study into different protection zones (PZs) corresponding to generator bus(es). Furthermore, a “gain in momentum” (GIM) index at each generator bus is used to minimize the search set. This information helps in reducing the search space to the PZ corresponding to the generator bus with highest GIM following a fault. This area is termed as a vulnerable protection zone (VPZ). Once the VPZ is identified, positive-sequence voltage magnitudes of each bus within the VPZ are monitored to locate the bus closest to the fault (BCF). Finally, reactive power-flow information of each line connected to the BCF is used to identify the faulted line. The performance of the proposed scheme is extensively validated on the Western System Coordinating Council-9 bus system, the IEEE-39 bus New England system, and 246-bus North India Grid using the Power System Simulation for Engineering. The test results indicate that the proposed scheme is highly effective for the WABP of transmission lines.

IPII based intelligent relay for TCSC compensated transmission lines: Tested on real time platform

The paper suggests integrated impedance based intelligent relaying for thyristor controlled series capacitor (TCSC) compensated transmission lines. The scheme uses a new relaying signal termed as imaginary part of integrated impedance (IPII). Integrated impedance is defined as the ratio of sum of the voltage phasors across two ends of the transmission line to the sum of the current phasors through two ends of the same transmission line. IPII of each phase of the transmission line is used as input to a data mining model known as decision tree (DT) which selects the faulted phase(s) involved in the fault process. The scheme is validated on Real time digital simulator (RTDS) platform. The test results obtained indicate that the proposed IPII based intelligent relaying is reliable in protecting of extra high voltage (EHV) transmission lines including TCSC.

A New Approach to Power System Disturbance Assessment Using Wide-Area Postdisturbance Records

This paper presents an empirical wavelet transform (EWT) based approach to perform postmortem analysis of wide-area measurement (WAM) based signals. The commonly used empirical mode decomposition (EMD) has limitations such as mode mixing, sensitivity to noise, and sampling rate. The decomposition provided by EWT is more consistent as compared to EMD. The modes revealed by the EWT help in extracting dynamic patterns of different power system disturbances. The dynamic patterns extracted through EWT-based decomposition are further used as inputs to a data-mining tool known as random forest, to build a wide-area disturbance classifier (WADC) model. The efficient mode extraction quality of the EWT-based signal processing tool is analyzed for WAM data recorded on Northern Grid of Indian Power System. The performance of the WADC is validated on IEEE 39-bus New England test system. The results provide improved performance in terms of decomposition quality and classification accuracy.

A New Adaptive Dependability-Security Approach to Enhance Wide Area Back-up Protection of Transmission System

This paper presents a new methodology to adaptively shift the dependability and security bias of the transmission system protection logic depending on the system state. Contingencies such as generator outage, line outage, and line fault can induce stressed system condition. Under stressed conditions, protection logic should be more biased toward security. Phasor measurement unit information is used at the system protection centre to estimate the system state. A data-mining model known as random forest is utilized to accomplish the task of state assessment. Two different protection logics are used to make the final relaying decision. The first protection logic is the existing distance relay and the second protection logic is based on wide area information. Both the protection logics are connected though logic gates to make the final relaying decision. The performance of the proposed scheme is validated on the IEEE-39 bus New England system and 246-bus Indian Northern Regional Power Grid system. The test results indicate that the proposed algorithm can help in shifting the dependability-security bias of the protection logic adaptively, which will help in mitigating cascaded outages in the power transmission system.

Exposing zone-2 and zone-3 mal-operations in thyristor-controlled series capacitor compensated transmission system

The paper investigates the potential challenges faced by conventional distance relays in case of thyristor controlled series capacitor (TCSC) compensated transmission systems. The mal-operations of back-up relays can trigger large scale cascaded outages. Detailed analysis on mal-operation of different zones of distance relay due to TCSC operation is carried out. The impact of TCSC on the relays of adjacent lines which provide back-up protection to the compensated line is observed. Finally, possible solutions to mitigate the problem associated with the impact of TCSC upon the conventional distance relays are discussed. The simulation studies are carried out on MATLAB environment.

Synchrophasors-Assisted IPII-Based Intelligent Relaying for Transmission Lines Including UPFC

Abstract This paper proposes a synchrophasors-assisted intelligent relaying scheme for transmission lines compensated by Unified Power Flow Controller (UPFC). The algorithm uses a new relaying signal termed as imaginary part of integrated impedance (IPII). The synchronized phasor measurements at both ends of the transmission line are used to extract voltage and current phasors from instantaneous voltage and current signals. The voltage and current phasors are utilized to derive IPII of each phase. Further, IPII of each phase is used as input to a data-mining model termed as decision tree (DT) which provides the final relaying decision. The proposed algorithm is validated on real-time digital simulator (RTDS) platform, and the results obtained indicate that the proposed scheme is both dependable and secure in protecting transmission system compensated by UPFC.