Capacitor Switching Transients Research Articles

Variable speed drives evaluation test

We present a test protocol and results of tests on pulse width modulated (PWM) drives rated at 3 hp and 20 hp and supplied from a 480 V line. The induction motor was turning a 25 hp computer-controlled DC dynamometer. This dynamometer was powered from the same source through a stepdown transformer and a regenerative controlled rectifier. Data (speed, torque, input voltages, currents) were collected and processed in a data acquisition system. The following tests were performed: efficiency and harmonics, voltage sags, and capacitor switching transients. Tests wee also conducted on three nontypical drive configurations.

Transient power quality problems analyzed using wavelets

In the literature, wavelet techniques have been proposed for the identification of power system transient signals (e.g., lightning impulse, and capacitor switching transients). In this paper, the wavelet technique is proposed for the analysis of the propagation of transients in power systems. The advantages and disadvantages of the method are discussed and the way in which these analysis methods complement previously reported identification methods is described. An example based on the discretized solution of a differential equation is given.

Application of distribution system capacitor banks and their impact on power quality

This paper presents a summary of the power quality-related concerns associated with the application of utility distribution capacitor banks. These concerns include distribution capacitor switching transients and power system harmonics. Methods for identifying these problems, determining their impact on utility and customer systems, and developing solutions are provided.

Capacitor switching and transformer transients

The impact of capacitor switching on transformer transients is evaluated. Two specific transformer failure events are described. Each of these failures coincided with the switching of a capacitor bank some distance away from the transformer. The causes of these failures are evaluated, and field-test transient voltage waveforms are duplicated by computer simulations. The simulation capability is extended to determine system conditions that are susceptible to these transient voltages as well as the means to minimize them.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Effect of Capacitor-Switching Surges on Insulation Aging and Incipient-Fault Breakdown of Distribution Cables and Accessories

This paper summarizes the finding related to the experimental evaluation of the effect of ringing switching surges on insulation aging and incipient-fault breakdown of distribution cables and accessories (CEA contract 092 D 234). The main emphasis in the present study was to reproduce test conditions as close as possible to the stresses observed in real distribution systems. This was done by first conducting extensive field recordings of capacitor-switching transients. The data obtained was used to define the characteristics of the test voltage to be reproduced in laboratory tests.

Effect of Capacitor-Switching Surges on Insulation Aging and Incipient-Fault Breakdown of Distribution Cables and Accessories

This paper summarizes the finding related to the experimental evaluation of the effect of ringing switching surges on insulation aging and incipient-fault breakdown of distribution cables and accessories (CEA contract 092 D 234). The main emphasis in the present study was to reproduce test conditions as close as possible to the stresses observed in real distribution systems. This was done by first conducting extensive field recordings of capacitor-switching transients. The data obtained was used to define the characteristics of the test voltage to be reproduced in laboratory tests.

Varistor versus Environment: Winning the Rematch

An unusual case of difficult application of surge protective devices was solved by field measurements with retrofit of protective devices suitable for the particular environment. Onsite measurements indicated that capacitor switching transients were causing excessive current surges in the varistors and fuses protecting the input to a thyristor motor drive. Knowledge of the environment gained by the measurements allowed understanding of the problem and specification of matching surge protective devices.

Station Capacitor Switching Transients - Analytical and Experimental Results

Station capacitor bank energization transients predicted by a circuit model are compared to field test results. Selection of a suitable model is discussed. A computer solution of the model is presented.