In this article we will discuss about power quality and issues relating to it. Power Quality: There can be completely different definitions for power quality, depending on one's frame of reference. For example, a utility may define power quality as reliability and show statistics demonstrating that its system is 99.98 percent reliable. A manufacturer of load equipment may define power [...]
One of the most frequently employed displays of data to represent the power quality is the so-called CBEMA curve. A portion of the curve adapted from IEEE Standard 4469 that we typically use in our analysis of power quality monitoring results is shown in Fig. 1.17. This curve was originally developed by CBEMA to describe the tolerance of mainframe computer [...]
The following points highlight the top seven devices used for measuring power quality. The devices are: 1. Multimeters 2. Digital Cameras 3. Oscilloscopes 4. Disturbance Analyzers 5. Spectrum Analyzers and Harmonic Analyzers 6. Combination Disturbance and Harmonic Analyzers 7. Flicker Meters. Device # 1. Multimeters: After initial tests of wiring integrity, it may also be necessary to make quick checks [...]
Standards are very important in the area of power quality monitoring. Power quality levels must be defined consistently and characterized using the same methods if they are going to be compared from one site to another and from one system to another. IEEE 1159 is the IEEE. Working Group that coordinates the development of power quality monitoring standards. The existing [...]
There are many applications for the intelligent power quality monitoring concept. Some of the more important applications are listed in this article: 1. Industrial Power Quality Monitoring Applications 2. Power System Performance Assessment and Benchmarking 3. Applications for System Maintenance, Operations and Reliability 4. Power Quality Monitoring and the Internet. 1. Industrial Power Quality Monitoring Applications: a. Energy and demand [...]
A Unified Power Quality Conditioner (UPQC) is a device that is similar in construction to a Unified Power Flow Conditioner (UPFC). The UPQC, just as in a UPFC, employs two voltage source inverters (VSIs) that connected to a dc energy storage capacitor. One of these two VSIs is connected in series with ac line while the other is connected in [...]
Power quality benchmarking is an important aspect in the overall structure of a power quality program. The benchmarking process begins with defining the metrics to be used for benchmarking and evaluating service quality. The EPRI Reliability Benchmarking Methodology project defined a set of PQ indices that serve as metrics for quantifying quality of service. These indices are calculated from data [...]
Power quality benchmarking is an important aspect in the overall structure of a power quality program. The benchmarking process begins with defining the metrics to be used for benchmarking and evaluating service quality. The EPRI Reliability Benchmarking Methodology project defined a set of PQ indices that serve as metrics for quantifying quality of service. These indices are calculated from data [...]
For many years, the only indices defined to quantify rms variation service quality were the sustained interruption indices (SAIFI, CAIDI, etc.). Sustained interruptions are in fact only one type of rms variation. IEEE Standard 1159-19957 defines a sustained interruption as a reduction in the rms voltage to less than 10 percent of nominal voltage for longer than 1 min. Sustained [...]
In this article we will discuss about power quality contracts and insurance signed by service providers to maintain the quality of electrical power supply. Power Quality Contracts: Once performance targets have been selected, utilities may enter into contractual agreements with end users with respect to power quality variations. While this is never an easy task, it was simpler when end [...]