Przemyslaw Balcerek

Accurate Noniterative Fault-Location Algorithm Utilizing Two-End Unsynchronized Measurements

This paper presents a new two-terminal impedance-based fault-location algorithm, which takes into account the distributed parameter line model. The algorithm utilizes unsynchronized measurements of voltages and currents from two ends of a line and is formulated in terms of the fundamental frequency phasors of symmetrical components of the measured signals. First, an analytical synchronization of the unsynchronized measurements is performed with use of the determined synchronization operator. Then, the distance to fault is calculated as for the synchronized measurements. Simultaneous usage of two kinds of symmetrical components for determining the synchronization operator makes that the calculations are simple, noniterative, and at the same time highly accurate. The developed fault-location algorithm has been thoroughly tested using signals of Alternate Transients Program-Electromagnetic Transients Program versatile simulations of faults on a transmission line. The presented evaluation shows the validity of the developed fault-location algorithm and its high accuracy.

A Fault-Location Method for Application With Current Differential Relays of Three-Terminal Lines

This paper presents a new method for locating faults on three-terminal power lines. Estimation of a distance to fault and indication of a faulted section is performed using three-phase current from all three terminals and additionally three-phase voltage from the terminal at which a fault locator is installed. Such a set of synchronized measurements has been taken into consideration with the aim of developing a fault-location algorithm for applications with current differential relays of three-terminal lines. The delivered fault-location algorithm consists of three subroutines designated for locating faults within particular line sections and a procedure for indicating the faulted line section. Testing and evaluation of the algorithm has been performed with fault data obtained from versatile Alternate Transients Program-Electromagnetic Transients Program simulations. The sample results of the evaluation are reported and discussed.

Fault Location on Double-Circuit Series-Compensated Lines Using Two-End Unsynchronized Measurements

This paper presents an accurate fault-location algorithm for double-circuit series-compensated lines. Use of two-end current and voltage signals is taken into account and a more general case of unsynchronized measurements is studied. Different options for analytical synchronization of the measurements are considered. The algorithm applies two subroutines, designated for locating faults on particular line sections, and in addition, the procedure for selecting the valid subroutine. The subroutines are formulated with the use of the generalized fault-loop model, leading to compact formulas. Consideration of the distributed parameter line model ensures high accuracy of the fault location. The proposed selection procedure allows for reliable selection of the valid subroutine. The developed fault-location algorithm has been thoroughly tested using signals taken from Alternate Transients Program-Electromagnetic Transients Program versatile simulations of faults on a double-circuit series-compensated transmission line. The presented fault-location evaluation shows the validity of the derived fault-location algorithm and its high accuracy.

Two-end unsynchronized fault location algorithm for double-circuit series compensated lines

This paper presents an accurate fault location algorithm for double-circuit series compensated lines. Use of two-end current and voltage signals with taken into account a more general case of unsynchronized measurements is studied. Different options for analytical synchronization of the measurements are considered. The algorithm applies two subroutines, designated for locating faults on particular line sections, and the procedure for selecting the valid subroutine. The subroutines are formulated with use of the generalized fault loop model, leading to compact formulae. Taking into account the distributed parameter line model assures high accuracy of fault location. Application of the proposed selection procedure allows for reliable selection of the valid subroutine. The developed fault location algorithm has been thoroughly tested using signals taken from ATP-EMTP versatile simulations of faults on a double-circuit series compensated transmission line. The presented fault location example shows the validity of the derived fault location algorithm and its high accuracy.

Improved unsynchronized two-end algorithm for locating faults in power transmission lines

A new two-end algorithm for locating faults in a single power transmission line is presented. Presence of the extra link between the line terminals is taken into account. A distance to fault is determined from unsynchronized measurements of voltages from both line ends and with additional, limited use of currents. Measured currents are utilized under the condition that they come from current transformers, which are not saturated. As a result of that, certain improvement of fault location - when comparing to the other known methods - is achieved. The delivered new algorithm has been tested with the fault data obtained from versatile ATP-EMTP simulations. The sample examples and results of fault location accuracy evaluation are reported and discussed in the paper.

Centralized substation level protection for determination of faulty feeder in distribution network

This paper presents a novel approach to design of a centralized substation level protection aimed at determining the faulty feeder in a distribution network. In opposite to phase-to-ground faults in the transmission networks (HV), impedance of phase-to-ground fault-loops in MV distribution networks is usually high. From all of these reasons, detection of ground-fault and determination of a faulty feeder at a bus-bar with many outgoing feeders arises as serious problem. However, during the ground-fault the transient component which provides important information about the disturbance in the system appears. Such signals consist of different frequency components, which result from charging or discharging of the network capacitances. In this paper new approach which is based on checking a phase displacement between a fundamental frequency component of zero sequence current and a voltage directly after the fault inception is presented. Provided simulation experiments in ATP/EMTP software package confirm the effectiveness of the proposed technique for selection of a faulty feeder during phase-to-ground fault in different and under different fault scenarios-different fault inception angles, including random mechanism and high resistance faults.

Optimization of distance protection algorithm for series-compensated transmission line

This paper is focused on optimizing the distance protection algorithm for series-compensated line. This algorithm requires estimation of three-phase voltage drops across capacitors bank. For this purpose a nonlinear differential equation is solved on-line, applying comparatively low sampling frequency. In order to assure high fidelity of the waveforms reconstruction using the up resampling procedure has been introduced. The other interest of this paper is in impedance calculation based on optimal solution of the fault loop model. Two methods for fault loop resistance and reactance calculation are taken for comparison. The developed algorithms have been tested and evaluated using signals taken from ATP-EMTP versatile simulations of faults on a series-compensated transmission line. The sample results of the evaluation are presented and discussed.

A method for internal and external fault discrimination for protection of series compensated double-circuit line

This paper presents a new method designated for determination whether detected fault is placed on a protected double-circuit line or outside the line. It suits for protection of parallel uncompensated or series-compensated lines and uses one-end phase currents measurements only. The developed algorithm has been tested and evaluated using signals taken from ATP-EMTP versatile simulations. A detailed model of considered transmission line including the SCs&MOVs banks as well as the measurement channels has been developed. Using this model, the reliable fault data on a double-circuit uncompensated/series-compensated transmission line as well as for faults outside the line have been generated under variety of fault conditions. The sample results of this evaluation are presented and discussed.

An Application of GPU Parallel Computing to Power Flow Calculation in HVDC Networks

Numerical computation on GPU has become easily accessible and offers good computation power for relatively little cost. Recently an application of Newton-Rap son method for analyzing power flow in multi-terminal high-voltage direct current (HVDC) networks was proposed and shown to have good results on five terminal grids. Since this method involves costly matrix operation, especially the inverse, increasing the number of terminals in the grid yields prohibitively large execution times in sequential operation. To address this issue, we adjust the algorithm so that it benefits from parallel computation and test our approach on recent GPU from NVidia. We give experimental results for grids up to few thousand terminals and show that execution time is still acceptable for real applications. We also provide some benchmarks of the GPU computation compared with other platforms.

Security and speed assessment of a new distance protection algorithm based on the wavelet transform

Distance relay algorithms are typically based on the phasor-domain approach where the fundamental frequency phasors are computed using well-known methods such as: the full cycle discrete Fourier transformation (FCDFT), least error squares (LES) and the discrete wavelet transform (DWT). Instead of the phasor-domain approach, there are time-domain based algorithms that detect faults without calculating the phasors. In this paper a new distance relay algorithm based on the time-domain approach and DWT is introduced. The security of fault detection and the tripping time obtained when applying the proposed algorithm to a number of fault simulations is compared with the equivalent results obtained when applying the classical solution based on DFT.