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An Overview of Power Quality Issues
Electrex Industrial Solutions
Your Partner in Electrical Service and Maintenance Since 1957

Overview of Power Quality Issues
Overview of Power Quality Issues
All businesses, from governmental to industrial, financial to commercial, require electricity. Power performs diverse tasks such as processing millions of dollars in transactions, providing heat and lighting, or producing sophisticated components. Businesses depend on power, and they depend on that power to be clean and reliable. Power disruptions result in lost production; jeopardize personal safety; increase fire hazards; reduce equipment performance, life and productivity; and affect data and communications. Power disturbances cost U.S. businesses an estimated $38.9 billion each year, making power quality a very serious issue. Power problems disturbances take many forms including outages, spikes, sags, and transients. Their impact varies from an immediate loss of power to barely discernible, but cumulative, costly results. And while quality power is essential, unlike other raw materials, power usage occurs in real-time. Power cannot be inspected before use and returned if unsatisfactory. Instead, businesses must monitor power to ensure it is as expected, and address disturbances with the proper electrical equipment. Since 1957, Electrex Industrial Solutions has helped businesses understand their power systems, and address the disturbances with equipment that negates its impact. When you understand the importance of power quality, you’ll see how easily this vital utility can work against you. Count on Electrex, with its experienced electrical service and maintenance team to help power work for you with power quality monitoring, solutions, and improvement.

What is a Power Disturbance?

Common types of power disturbances include outages, transients (surges), harmonic distortions, electrical noise, voltage sag, and voltage swells. They are characterized by reset or locked-up computer controls; momentary light flickering; overheating of transformers or motors; frequent circuit board failures; tripped circuit breakers and blown fuses; loss of stored data; premature equipment wear and/or failure; unexplainable equipment operational abnormalities; activation of alarms without cause; and high electric bills.

What are Outages?

Outages are an easy-to-detect power disturbance because they are simply the absence of power. Outages are typically caused by a breaker opening or a fuse blowing in order to protect equipment, or because of safety concerns.

What are Transients?

Transients, more commonly known as power surges, result from abnormal conditions on the power system. The abnormal conditions may be dramatic – lightning strikes cause severe transients because of high voltages and currents; they may also be routine. Activating motors, drives, and transformers, turning on fluorescent lights and fax machines (known as switching of inductive or capacitive loads) are the most common cause of transients in factory or business environments. The effect and severity of the transient disturbance depends on the magnitude, duration, and frequency of the transient. Low-energy transients cause electrical equipment to malfunction, while high-energy transients can damage equipment.

What are Harmonic Distortions and How Can They Damage Equipment?

Due to their internal electronics, certain commonly-used devices – like variable speed drives, PCs and telecommunications equipment – generate harmonic currents. When these currents combine with the facility current, the voltage is distorted. This distortion results in misoperating controls, overheating of motors and transformers, erratic equipment operations, and capacitor failures. Harmonics can also cause unwanted noise on communications and data lines, and can lead to blown fuses and/or loss of computer data.

What is Electrical Noise?

An electrical noise is characterized by the presence of unwanted electrical signals. Common causes include ground loops, which act like antennas to pick up noise and allow it to flow through computer data line shields into circuitry. Hand-held walkie-talkies and cellular phones have also been known to create interference and disturbances around sensitive equipment.

What are Voltage Sags?

Voltage sags are temporary decreases in voltage that may last up to a few seconds in duration. They cause equipment disruptions – resulting in data loss, “hiccups,” or even shutdown. Typically, sags occur when temporary faults are placed on the utility system, such as lightning strikes, tree or animal contact with power lines, or vehicle contact with a pole. Sudden, increased demand for current within a facility, such as welding or daily power-up, can also cause sags … until the demand decreases.

What are Voltage Swells?

Voltage swells are temporary increases in voltage that may last for a few seconds. The most common cause of destructive swells is a loose neutral connection. The effects of a swell can be more physically destructive to equipment than those of a sag. High voltage can cause a breakdown of components in the power supplies of equipment. This can be a gradual or cumulative effect, leading to premature equipment failure and erratic operation.

Why Should I Have My Equipment Monitored?

Continuous monitoring provides the data needed to determine how, when, and where power disturbances occurred. The data leads to an understanding of how these disturbances may be avoided in the future and how the effects may be decreased and improved. Monitoring also provides useful data for planning future plant expansion and for ensuring that existing or future facilities will be adequate. It is also useful for planning the addition of new discrete loads or backup power systems.