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We aim to solve the OPF problem by defining contingency scenarios involved in the optimization problem by means of a SDP relaxation. Contingency scenarios are performed for the IEEE 39-bus system. Contingency analyses are performed by generation and line losses. Contingency scenarios are considered to be possible events. These events may be single contingencies, such as a generation unit failures...
The electric power system is a complex system, whose operating condition may not remain at a constant value. This necessitates the power system operator be alert to keep the system performance under normal condition. The various contingencies like, large load variations, outage of components (transmission lines, transformers, generators, etc.) are more common. Any of these conditions causes overloads...
This article presents an analysis of the behavior of the electrical frequency in Caracas during four major events of the year 2008. The frequency was computed from the voltage signals of the fault recorders. The events of April 29 and September 01 were faults in transmission lines of the National Grid, and the event of October 19 was the erratic trip of two main lines at 765kV (Guri-Malena). In these...
A typical power system voltage collapse scenarios is often ended with the undesirable operation of the Zone-3 distance relay of the transmission lines. This paper presents a protection scheme to avoid power system voltage collapse using a combined method of distance relay's Zone-3 blocking scheme and a sensitivity-based load shedding selection. The Zone-3 distance relay blocking is based on the proper...
The Uruguayan power system is highly dependent on two 500 kV transmission lines connecting the largest generation site (Salto Grande) and the Argentinean interconnection in the North, to the largest loading area in the South. Actual occurrences, where both 500 kV lines tripped, lead the system to widespread blackouts including the critical area of Montevideo, the nation's capital district. This paper...
A security scheme of the power systems should protect the integrity of the electric networks and carry out fast operations on the entire power system to prevent a possible blackout. Blackouts started as local failures led to electrical disturbances, and the complete collapse of the power systems. This work proposes a security scheme based in two stages. In the first stage, the controlled separation...
Network operation is being increasingly impacted by the changing load dynamics served by distribution utilities, and increasing dependence on generation that is located remotely from load centers. Investigations following recent blackouts, point out that the main reason for many of the major power system instabilities is voltage collapse. This paper proposes a co-ordination method for load shedding...
A variety of emergency controls for the prevention of cascading blackouts are generator tripping, fast valving, load shedding, excitation controls and controlled islanding. Controlled power system islanding operation is one of the effective actions made by operator at the dispatch center. Through the centralized control scheme, the operator should decide which transmission lines to be opened to split...
Our study aims at minimization of power not supplied (PNS) under the severe fault condition such as a tripping of transmission lines. In this paper, we propose a new static control method which can minimize PNS by coordinately controlling multiple unified power flow controllers (UPFCs), generators and loads. The proposed method is based on multiple optimal power flow (OPF) calculations, and determines...
At stressed operating conditions, critical contingencies can initiate loss of synchronism and trigger cascading events. Controlled islanding is the last line of defense to stabilize the whole system. This paper presents a decision tree assisted scheme to determine the timing of controlled islanding in real time by using phasor measurements. In addition, a slow coherency based approach is used to determine...
On April 26th, 2007, at 9:58 a.m., a fault on the Colombian power system caused by maintenance in the 230 kV Torca Bus gave origin to black out. The consequent loss of those important branches caused cascading outages of tie lines that turned out in cascade events that concluded in an electrical separation with Ecuador, causing many economical losses for the country. The Colombian power system frequency...
Investigations of recent blackouts indicate that the root cause of almost all of these major power system disturbances is voltage collapse rather than the underfrequency conditions prevalent in the blackouts of the 1960s and 1970s. The operation of today's power system with generation frequently being remote from the load centers has made the power system very dependent on the utility transmission...
Power system defensive islanding is an efficient way to avoid catastrophic wide area blackouts, such as the 2003 North American blackout. Finding defensive islands of large scale power systems is a combinatorial explosion problem. Thus, it is very difficult to find an optimal solution, if it exists, within reasonable time using analytical methods. This paper proposes utilizing the computational efficiency...
Investigations of recent blackouts indicate that the root cause of almost all major power system disturbances is voltage collapse rather than the underfrequency conditions prevalent in the blackouts of the 1960s and '70s. This paper explores the nature of recent power system blackouts (2003 east coast, 1996 California and others) and explains why voltage is the leading edge indicator of impending...
This paper discusses why voltage as well as frequency load shedding may be necessary to prevent major system blackouts. Investigations of recent blackouts indicate that the root cause of almost all of these major power system disturbances is voltage collapse rather than the underfrequency conditions prevalent in the blackouts of the 1960 and '70s. This paper explores the nature of recent power system...
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