Power Quality (PQ) Monitoring

What Is Power Quality (PQ) Monitoring?

Power quality (PQ) monitoring is a tool used to help experienced expert PQ engineers see inside customer electrical systems & understand how electrical / electronic equipment reacts to unfavorable voltages. Monitors are used because standard volt / amp meters (& basic PQ monitors) cannot provide the level of detail required to understand & identify the interactions between electrical systems & end-use equipment. These interactions are what causes systems & equipment malfunctions, damage & failures. Carefully selecting & setting up the right monitor(s) provides tools useful to an experienced PQ engineer. Although monitors are designed to measure & record voltage & current behavior versus time & frequency for long periods of time, years of experience is necessary to ensure the right information is recorded & interpreted correctly. Recordings are needed to help PQ engineers understand how, when, when & where electrical problems develop. Monitoring alone will not provide enough information to understand, identify, solve & prevent system & equipment problems.

Unfortunately, the selection, installation & setup of PQ monitors, like many advanced electrical instruments, comes with challenges just as reading / interpreting PQ monitoring data does. People with little to no experience in PQ find themselves unable to read / interpret monitoring data & link it to system & equipment malfunctions, damage & failures. After the fact, they realize the monitor wasn’t installed or setup correctly, which means it won’t record the right voltage & current data necessary to understand, identify, solve or prevent the problem.

One useful area of experience, possessed by PBE engineers, is advanced knowledge regarding how many end-use equipment (VFDs, motors, PLCs, electronic lighting & power supplies, etc.) responds to common every day electrical disturbances including the normal & abnormal ones. Knowledge of how electronic equipment is designed helps but is not enough to “fill in the gaps” required to successfully diagnose a PQ-related system and/or equipment problem. This becomes even more challenging since many of the PQ phenomena occurring in customer electrical systems is high frequency in nature, especially when (and most do) customer facility electrical systems contain many wiring & grounding (W&G) problems. This makes the art of understanding, identifying, solving & preventing (UISP) PQ problems even more challenging.

Much experience with PQ disturbances is also needed to read / interpret monitoring data. Specific types of disturbances have unique waveforms (or shapes), names, causes & impact systems & equipment differently. The problems in W&G systems in customer facilities also play a vital role in shaping disturbances by the time they reach the affected equipment. Without the ability to sort through the many “funny looking” trends & waveforms found in all PQ data, novices will experience difficulties in determining the next steps needed to understand, identify, solve & prevent (UISP) system & equipment problems. Correct interpretation of PQ data narrows down the paths an experienced PQ engineer needs to take to get to the root causes of the problems.

Another common pitfall associated with PQ monitoring is knowing the right instrument to use for a customer facility PQ investigation. Not all monitors are created equally, and not all monitors are designed & tested to the same industry standards. Monitors are like cars—you can purchase a cheaper car with limited performance, or you can purchase the right car that will do the job. In fact, not all monitors are suitable for harmonic studies, for example. PBE has extensive experience in monitor design, performance, certification, communications, testing & applications.

Many customers have contacted PBE disappointed to find they’ve chosen the wrong monitor and/or selected the wrong resource to conduct the monitoring needed to try & understand their PQ problem. Inexperienced users frequently find that a monitor didn’t record any data because it wasn’t set up correctly. Customers should be aware that not all electrical engineers have enough experience to conduct monitoring, manage & analyze data, articulate results to customers & make the right, most practical recommendations to solve & prevent PQ problems.

PBE is an advocate for permanent PQ monitoring on utility power systems, on customer building electrical systems & at critical equipment. Permanent PQ monitoring allows customers to record historical PQ behavior needed to establish a baseline of PQ performance at selected critical points on a system. Another benefit of permanent PQ monitoring is the ability (with certain monitors) to incorporate other critical signals such as temperature, pressure, humidity, proximity, vibration, speed, etc. with the voltage & current behavior of electrical systems & end-use equipment. PBE has completed 100’s of permanent PQ monitoring projects for customers in the US & around the globe. PBE has relationships with many monitoring manufacturers in the US & around the globe.

PQ monitoring services can be combined with any other PBE PQ engineering service to help customers address their layer of PQ problems while making the cost as economical as possible. Contact PBE to have us conduct PQ monitoring for you. When we engage with customers regarding monitoring, the process of starting to learn about PQ & why it is important to the life, reliability & performance of every electrical system & piece of equipment & to the health of your bottom-line profits.