Consumption, faults and mistakes on the electricity distribution networks causes unstable voltage levels at the end user interfaces. Voltage might be normal at a neighborhood while it is at lower or higher ratings on at other districts. On the other hand, certain process periods have enormous amounts of diffrence at electricity consumption thiis is also one of the main reasons of the voltage diffrences. In additions, sudden and short or continuous changes could occur at network voltage, beside off all these mentioned main reasons. These voltage changes could cause damages on electrical devices, equipments, and industrials machines. Therefore, these problems might cause loss of production, losing vcaluable equipments, losing a certain amount of money. These kind of damages could be prevented by the usage of required voltage stabilizers, regulators, and stable power supplies. A voltage regulator analyze, increase, or decrease the voltage level and provide stable as required, voltage at unstable voltage levels. Current developments on technology and increasing personal needs bring more and more electronics to our daily life, which brings a new requirement for the constant and stable voltage suppliesand voltage regulators.

In order to save the economical balances and to survive, in tjough conditions of globalization, which we feel effects and requirements harder day by day; people need to get into a industrialization process. Therefore, this period has brought a huge energy demand which people and distribution networks are not satifactory against the demand. Huge investments requirement in order to establish a healthy and satisfactory energy distribution network is also another problem. Missing coordination between Consumer and Supplier and finally unbalanced energy demand are other problem sources. As a result, we can show; rapid industrial developments, energy demand, industrial regions/areas, and even unorganized population settlements as the reasons of energy distribution networks problems.

Network oscillations are voltage variations at an energy distribution network and these variations amed regarding the act decrease or increase. Voltage variation at energy distribution network can be classified regarding the act; the rapid ones are short ones (increase or decrease) and long periodic or permanent ones. Rapid voltage increases or decreases usually occur while distribution network voltage is temporarily low or high. However, long periodical falls occurs because network voltage is always low. We can mention; fully loaded power sources (power transformers), miscalculated power distribution lines, grounding mistakes are the main examples of long periodic or parmanent voltage decrease. Raid voltage variations, mostly takes very short time such as sensitive automatic switch on-ofis, voltage demurrage during the startup huge powerhouses such as pumps and compressors are also gathers high current at the startup. Voltage rises may occur due to atmospheric events and shutting down the great loads such as in the example of switching off the energy centrals.