Power Transmission

Paper on RTV High Voltage Insulator Silicone Rubber Coatings as presented at the CIGRE CBIP Conference on Insulators in EHV/UHV Transmission Systems in New Delhi on 12 NOV 2018.

The paper covers trends, developments, new studies of RTV HVIC coated equipment in suspension and tension orientation, partially and fully coated insulators, and the performance of quartz and ATH fillers.

A comprehensive study of capacitor placements and real-time control in general unbalanced distribution systems is undertaken. New developments in a loss reduction formula, problem formulations, solution methodology and mathematical justification are presented. The problem is decoupled into two subproblems: the capacitor placement subproblem and the real-time control subproblem. An effective solution algorithm for placing capacitors and determining their real-time control

Converting existing AC lines to DC for increasing power transmission has been an interesting topic for scientists, such applications could be managed by conventional converters. Converting AC lines to DC upgrades the power capacity of existing lines up to square root of two. In this paper, a modified converter that would use all three existing AC lines at the same

This work describes the structure and regulation of transmission-related activities in Brazil, and assesses their effectiveness/limitations when addressing issues such as network expansion, locational pricing, transmission financial rights, and others. The paper also discusses the cross-border energy trading between Brazil and neighbor countries, and the perspectives of an integrated regional electricity market.

An active machine learning technique for monitoring the voltage stability in transmission systems is presented. It has been shown that machine learning algorithms may be used to supplement the traditional simulation approach, but they suffer from the difficulties of online machine learning model update and offline training data preparation. We propose an active learning solution to enhance existing machine learning applications by actively interacting with the online prediction and offline training process. The technique identifies operating points where machine learning predictions based on power system measurements contradict with actual system conditions. By creating the training set around the identified operating points, it is possible to improve the capability of machine learning tools to predict future power system states. The technique also accelerates the offline training process by reducing the amount of simulations on a detailed power system model around operating points where correct predictions are made. Experiments show a significant advantage in relation to the training time, prediction time and number of measurements that need to be queried to achieve high prediction accuracy.

This paper highlights on continuous improvement in Extra High Voltage (EHV) & High Voltage (HV) AC Underground Transmission Cables (UTC) Technology like real time monitoring, improved XLPE insulation. Due to improvement in manufacturing technology & long-term technical experiences of cable manufacturers with EHV XLPE cable systems, there is increase in reliability of cable. For UTCs accessories, a high level of quality & reliability has been achieved with the technology of pre-fabricated & pre-tested insulation bodies of silicone rubber. Frequency of internal failure in XLPE insulated UTC is very low of value 0.088 as compared to failure in 230 kV Overhead Transmission line (OTL) =0.7997. This paper is based on the recent Service Experience & statistical data obtained from TSO, Working Groups, & EHV XLPE UTC manufactures.

Power system stability is the capability of power systems to maintain load magnitude within specified limits under steady state conditions in electrical power transmission. In modern days, the electrical power systems have grown in terms of complexity due to increasing interconnected power line exchange. For that, an inherent of controllers were essential to correct the deviation in the presence of external disturbances. This paper hence aims to review the basic concepts of power system stability in load frequency control. Various control techniques were analyzed and presented. Power system stability can be classified in terms of method to improve power system stability, which are rotor angle stability, frequency stability and voltage stability. It is found that each method has different purpose and focus on solving different types of problem occurred. It is hoped that this study can contribute to clarify the different types of power system stability in terms of where it occurs, and which is the best method based on different situation.

Control techniques that optimize the behaviour of pulse-width modulation (PWM) rectifiers for magnet supplies are examined. Different control strategies, both with preprogrammed and variable switching patterns, are examined and compared in terms of optimization of the system performance. Optimum digital PWM, multilevel delta modulation, and hybrid PWM/delta techniques are analyzed. The validity of the control methods was verified by simulation and experimental tests on a 60 kW prototype. It was observed that, in practice, digital PWM techniques are better suited for optimizing the AC converter performance, while delta modulation techniques give better results in terms of DC current and voltage distortion.>

SUMMARY The Randstad 380 project is a plan of the Dutch transmission system operator to upgrade the transmission grid in the densely populated provinces Noord-Holland and Zuid-Holland. This project is deemed necessary to prepare the grid for the future. The proposed solution by the TSO TenneT is an ac overhead line of 3800 MVA. However, part of the Randstad 380 project, the connection Beverwijk-Bleiswijk, calls for special attention because of a number of specific issues. A study has been performed to assess the possibility of applying 1100 MW, 300 kV VSC HVDC for this connection. This paper discusses the technical viability of state-of-the-art VSC HVDC for bulk transmission of power in a meshed grid by investigating the Beverwijk-Bleiswijk connection and offers a framework for evaluation of other projects. It is also shown that VSC HVDC can be a cost- effective alternative to ac connections in a meshed grid.

The new, 160 mile long Amtrak Northeast Corridor railway electrification project has four supply substations that connect 115 kV utility power to the 55 kV single-phase, AC traction power system. Eighteen autotransformer-paralleling stations are spaced along the route. Each autotransformer connects the overhead catenary to an auxiliary feeder line, with the rails tied to an intermediate point of the autotransformer. Each train draws power from two adjoining autotransformers. The protection scheme includes distance protection for the catenary and feeder lines, transformer protection for the power transformers and autotransformers, plus bus protection and backup protection. The protection scheme uses a specialized type of numerical distance protection relay optimized for railway traction systems. In the event of a fault on the protected part of the line, a trip occurs and the relay calculates the distance to the fault. All the autotransformers within that distance are automatically disconnected, and the relay attempts a reclose. If the reclose is successful, the autotransformers are reconnected

The Leyte-Luzon HVDC power transmission system has achieved a converter availability of 98% during its first 15 months of commercial operation. Despite AC network constraints the commissioning tests were able to optimise the controls and demonstrate the effectiveness of the special frequency and emergency power controls in stabilising both the Leyte and Luzon networks. The performance measurements confirmed that the

RTV Insulator Coatings are being recognized as perhaps the most effective methods to eliminate pollution flashovers on ceramic insulators of up to 1200kV. Power utilities, heavy industry (captive power), technical consultants and academics are increasingly researching the subject. This presentation on Gen-4 RTV Insulator Coatings was for an IEEE event at Indian Institute of Technology (IIT, Delhi) and explains various key aspects of the coating. Contact [email protected] for more information