As you begin your journey into the world of power quality, many new and unfamiliar terms may present themselves. TCI is committed to educating our clients about the vast world of power quality. To help you in this capacity, we have attempted to answer some of the questions we hear most often from our clients. If you have a question you’d like us to add, feel free to contact us.

How do you define power quality?
Power Quality is a set of metrics used to benchmark the quality of the electric service provided to customers. The American National Standards Institute (ANSI) and the Electric Power Research Institute (EPRI) have developed power quality metrics that most electric utilities in the United States use to measure the quality of electricity being delivered. Using national standards ensures that electric utilities, equipment manufacturers, consultants, and end users have a common understanding of the electric service that is expected at the interface point between the utility and the customer’s premise.

What are harmonics?
Harmonics are multiples of a singular base frequency, each with its own frequency and amplitude. Each harmonic is sinusoidal and as such repeats through an electrical system. Harmonics in our electrical systems today are caused by nonlinear loads such as personal computers and variable speed drives. These harmonics are introduced to the system through the way the load draws current.

What are transients?
Transients, or transient voltages, are momentary changes in voltage or current that occur over a short period of time. This time interval is usually described as a cycle or about 16 milliseconds. Many transients can last microseconds (10 times as long). Transients are commonly known as "surges" or "spikes" and account for 88% of all electrical “down-time.”