Econonical aspects of supply network operation

Both electric Utilities and end users of electrical power are becoming increasingly concerned about thè quality of electric power. The term power quality has become one of thè most prolific buzzwords in thè power industry since thè late 1980s. It is an umbrella concepì for a multitude of individuai types of power system disturbances. The issues that fall under this umbrella are not necessarily new. What is new is that engineers are now attempting to deal with these issues with a systems approach rather than as individuai problem. There are four major reasons for thè growing concern: 1. Load equipment is more sensitive to power quality variations than equipment applied in thè past. Many new load devices contain rhicroprocessor-based controls and power electronic devices that are sensitive to many types of disturbances. 2. The increasing emphasis on overall power System efficiency has resulted in a continued growth in thè application of devices such as high-efficiency, adjustable-speed motor drives and shunt capacitors for power factor correction to reduce losses. This is resulting in increasing harmonic levels on power systems and has many people concerned about thè future impaci on System capabilities. 3. Utility customers are becoming better informed about such issues as interruption, sags, and switching transients and are challenging thè Utilities to improve thè quality of power delivered. 4. Many things are now interconnected in a network. Integrated processes mean that thè failure of any component has much more important consequences.