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The following topics are dealt with: microgrid system; power distribution system; smart power grid; power transmission planning; power cables; lightning arrester; FACTS devices; wind power plant; load flow; photovoltaic solar system; electric traction system; double feed induction generator; power generation control; hydroelectric power plants; relay protection; VSC HVDC station; genetic algorithm;...
This paper summarizes the main results about design and evaluation of a device to reduce Transient Recovery Voltage (TRV) magnitude in medium voltage switching equipments. Zinc Oxide (ZnO) devices are modeled in an Electromagnetic Transients Program (EMTP), being applied as an alternative to limit TRV peaks in circuit breakers and reclosers of 15 kV and 72.5 kV voltage class. The assessment of device...
The objective of this paper is to present the current status and state-of-the-art of microgrid systems as well as the barriers that are being encountered for their integration to the network. The expectation about the microgrid performance is high, thus, issues related to the microgrid standards, autonomous operation, control strategies, regulatory barriers as well as its protection and islanding...
This paper investigates the influence of basic TCSC main circuit structure and control on subsynchronous torsional damping of a nearby turbine-generator. An improved s-domain model based on dynamic phasor approach was used to obtain the results presented in the paper. The study is conducted on the System-1 of the IEEE Second Benchmark Model. Detailed eigenvalue analyses are carried out in order to...
This paper presents a case study on the failures of three 230 kV XLPE cables. These cables failed after only 4 years of service. It was found that the copper woven fibre glass (CWFG) tape and the water swellable tape had many burnt stains. The causes of these stains were analysed. It was proved from theoretical analysis and experimental investigations that there was a problem of bad contact between...
In order to identify possible shortcomings at design and manufacturing level, polymeric insulators are subjected to various tests at the laboratory established in ANSI C29.13-2000 and IEC 61109-1995 norms. One of these are environmental, which is done via simulations in laboratories, but these never become so severe and demanding as the present conditions of operation in the field. Therefore, this...
Ancillary services are some operational reserved services procured by the Transmission System Operator (TSO) for keeping a balance between supply and demand, stabilizing the transmission system and maintaining the power quality on an economical basis in any competitive electricity market environment. This paper discusses different types of ancillary services and their characteristics and challenges...
This paper proposes a new approach for optimal phasor measurement units placement for fault location on electric power distribution systems using Greedy Randomized Adaptive Search Procedure metaheuristic and Monte Carlo simulation. The optimized placement model herein proposed is a general methodology that can be used to place devices aiming to record the voltage sag magnitudes for any fault location...
The continuity of electric energy supply to consumers is a permanent objective of the power utilities, pursuing the development of technological solutions to improve the performance of the power re-establishment in contingency conditions. The main purpose is to minimize the impact on the number of consumers affected and reduce the time required to re-establish the energy supply. In this way, the power...
The phases of a transmission line are tightly coupled due to mutual impedances and admittances of the line. One way to accomplish the calculations of currents and voltages in multi-phase lines consists in representing them in modal domain, where its n coupled phases are represented by their n propagation modes. The separation line in their modes of propagation is through the use of a modal transformation...
This article shows the advantages of using transmission lines with ACSR (Aluminium Cable Steel Reinforced) ground wires in the neighbourhood of high voltage power substations. The concept of selfneutralized current is reminded in order to explain why the utilization of a double ACSR ground wire 7-20 km from the transmission line terminal substations is able to reduce up to 65% the value of the terminal...
This article reports measurements carried out at Lactec high voltage laboratory. It also shows how to use Steinmetz Circuit Theory to obtain computed results very similar to measured values. The article also comments how difficult it is to obtain the same results using Shelkunoff Transfer Impedance Theory. The article also recalls basic principles of cable shielding technique.
This article presents a summary of the standard design procedures successfully used by several Brazilian utilities to control electromagnetic interferences in power plants, substations and telecommunication installations. Those users stated in articles and conferences that the reported procedures controlled very well the interference problems in their facilities. The article shows that usual cable...
This article presents a critical analysis of the 3 different methodologies to determine the suitable location of lightning arresters that are simultaneously accepted by some Brazilian and international standards.
This paper proposes a heuristic constructive multi-start algorithm (HCMA) to distribution system restoration in real time considering distributed generators installed in the system. The problem is modeled as nonlinear mixed integer and considers the two main goals of the restoration of distribution networks: minimizing the number of consumers without power and the number of switching. The proposed...
This paper presents a new methodology for solving the optimal VAr planning problem in multi-area electric power systems, using the Dantzig-Wolfe decomposition. The original multi-area problem is decomposed into subproblems (one for each area) and a master problem (coordinator). The solution of the VAr planning problem in each area is based on the application of successive linear programming, and the...
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