Redundancy-based approach for optimal number and location of power quality monitors in distribution systems with binary imperialist competitive approach

This article deals with optimal employment of power quality monitors (PQMs) in distribution networks on the basis of the idea of monitor reach area. The proposed model uses binary string, representing the installation mode of PQMs (Yes or No) in each bus of the network. In the current article, the binary version of the imperialist competitive algorithm (BICA) is used. Because it has the ability of enhancing the search potential with a rapid and secure convergence rate in the optimization process. The concept of redundancy is considered in this study. The overall cost function is formulated to optimize the two indices. The first one is the index of monitoring overlap, and the second one is the index of sag severity. Among the solutions that yield a full reachable power network and the objective function experiments the minimum value, the final optimal answer will be extracted through evaluating the redundancy. With an excellent redundancy with respect to other solutions, the buses of the system faced with faults are monitored more times, on an average. In the current research, DIGSILENT software is used in short-circuit analysis, whereas the BICA manages the optimization process. Simulation and comparison are performed on the 69-bus distribution system

OPTIMAL NUMBER AND PLACEMENT OF POWER QUALITY MONITORS FOR MONITORING VOLTAGE SAG IN POWER SYSTEM NETWORKS

The occurrence of voltage sags often interrupt the operating process of modern equipment, especially in manufacturing and semiconductor plants. To avoid high production loss in industries, power quality monitoring is essential. Monitoring the whole power system will provide important data to a utility company. As most power system networks are large, allocating a Power Quality (PQ) monitor at every bus in the system is costly. Therefore, the optimal number of PQ monitors should be determined. In this thesis, an optimum number of PQ monitor locations is identified through a searching procedure developed based on the method of fault position combined with certain network characteristics such as the number of connecting lines and the size of the coverage area, or sag vulnerability area. The proposed searching procedure will be enhanced with the usage of monitor redundancy level. To allow redundancy in monitoring sags, a minimum of three recordings are required. This is to allow functioning of two recordings when a monitor fails. The monitor redundancy criterion is used to ensure that every fault in the power system can be observed and validated with sufficient redundancy to ensure the monitoring system is not affected when one of the monitors fails to function. The monitor searching procedure is developed by using the MATLAB software. The monitor searching procedure is simulated to three different IEEE standard test systems: IEEE 30, 118 and 300 bus systems. Simulation results demonstrate that it is possible to monitor the occurrence of a voltage sag in the entire power system with an optimum number of power quality monitors. The monitor searching procedure is then validated through the implementation of monitoring the voltage sag event in the Peninsular Malaysia’s utility network project. The number of monitors used under this project has been able to record sag events with optimum redundancy and the introduction of remote monitoring has enhanced the monitor searching procedure as the monitors used are able to upload data automatically to the database

Power quality and electromagnetic compatibility: special report, session 2

The scope of Session 2 (S2) has been defined as follows by the Session Advisory Group and the Technical Committee: Power Quality (PQ), with the more general concept of electromagnetic compatibility (EMC) and with some related safety problems in electricity distribution systems. Special focus is put on voltage continuity (supply reliability, problem of outages) and voltage quality (voltage level, flicker, unbalance, harmonics). This session will also look at electromagnetic compatibility (mains frequency to 150 kHz), electromagnetic interferences and electric and magnetic fields issues. Also addressed in this session are electrical safety and immunity concerns (lightning issues, step, touch and transferred voltages). The aim of this special report is to present a synthesis of the present concerns in PQ&EMC, based on all selected papers of session 2 and related papers from other sessions, (152 papers in total). The report is divided in the following 4 blocks: Block 1: Electric and Magnetic Fields, EMC, Earthing systems Block 2: Harmonics Block 3: Voltage Variation Block 4: Power Quality Monitoring Two Round Tables will be organised: - Power quality and EMC in the Future Grid (CIGRE/CIRED WG C4.24, RT 13) - Reliability Benchmarking - why we should do it? What should be done in future? (RT 15

Quantifying the benefits and risks of real-time thermal ratings in electrical networks

PhD ThesisReal-Time Thermal Rating (RTTR) is a technology that allows the rating of electrical conductors to be estimated using real-time, local weather conditions. In many cases this leads to an increased rating with respect to conventional approaches. It also identifies some instances in which the conventional, static, rating is greater than the true rating, and is therefore potentially unsafe. The work in this thesis comprises methodologies to improve the planning and implementation of RTTR. Techniques commonly employed in the wind energy industry have been modified for use with RTTR. Computational wind simulations were employed to allow the identification of determining conductor spans, to inform network designers of the rating potential of different conductor routes, to estimate the additional wind energy that could be accommodated through the enhanced line rating and to allow informed placement of the monitoring equipment required to implement RTTR. Furthermore, the wind simulation data were also used to allow more accurate estimation of conductor ratings during operation. Probabilistic methods have been devised to estimate the level of additional load that could be accommodated through RTTR, and quantify the risk in doing so. Finally, a method has been developed to calculate the benefit RTTR can provide to system wide reliability. State sampling and sequential Monte Carlo simulations were used to evaluate the probabilistic functions associated with the ratings, the load and failures on both the existing network and the RTTR system itself. These methods combine to address fundamental barriers to the wide scale adoption and implementation of RTTR. The majority of existing research has focussed on improving technical solutions, which are of little benefit if it is not possible to quantify the benefits of RTTR before it is implemented. This work allows quantification not only of those benefits, but of the associated risks and uncertainties as well