Electrical power measurements are important quantities, which must be measured precisely. Electrical power systems are dependent upon accurate measurements for everyday operation. Thus, many types of measurements and measuring equipment are associated with electrical power systems. Measurement fundamentals will be discussed in the following sections.
Today, most nations of the world use the metric system of measurement. In the United States, the National Bureau of Standards began a study in 1968 to determine the feasibility and costs of converting the nation to the metric measurement system. Today, this conversion is incomplete. The units of the metric system are decimal measures based on the kilogram and the meter. Although the metric system is very simple, several countries have been slow to adopt it. The United States has been one of these reluctant countries, because of the complexity of actions required by a complete changeover of measurement systems.
Units of measurement have a significant effect on our lives, but we often take them for granted. Almost everything we deal with daily is measured by using some unit of measurement. For example, such units allow us to measure the distance traveled in an automobile, the time of day, and the amount of food we eat during a meal. Units of measurement have been in existence for many years;
However, they are now more precisely defined than they were centuries ago. Most units of measurement are based on the laws of physical science. For example, distance is measured in reference to the speed of light, and time is measured according to the duration of certain atomic vibrations.