Power Quality Portal Project

Why This Matters

Power quality and reliability are critical for commercial customers, especially those in high-technology industries. Even sub-second voltage dips, swells or outages can shut down essential equipment, and interrupt product development and production processes. At the same time, power quality and reliability are becoming more difficult to manage. Variable renewable resources such as solar and wind are expanding on the grid, as are large and intermittent loads such as electric vehicle charging.

What is a power quality event? waveforms graphic

Historically, power reliability has been measured in terms of the frequency of power outages lasting longer than 5 minutes. Utilities metrics such SAEDI [System Average Interruption Duration Index] and SAIFI [System Average Interruption Frequency Index] define and track reliability. Momentary outages and power quality are related, but involve a much finer level of resolution.

Momentary outages, defined as zero voltage events lasting for less than five minutes, are measured via MAIFI [Momentary Average Interruption Frequency Index]. Even momentary outages can represent a material business issue, as an EPRI study found the average impact of a one-second outage for a commercial facility was 21 minutes in downtime.

Disturbances 1996 Duration of facility outage

Yet sustained and momentary outage metrics don’t reflect the full range of power disturbances that result in customer impacts. Power quality is further defined as ‘any occurrence manifested in voltage, current or frequency deviations which results in failure or mis-operation of end use equipment.'

Sub-second voltage dips or swells greater than 30% of nominal often also result in customer impacts, as defined by indices such as the CBEMA-ITIC curve. And typical of many commercial and industrial zones with older utility infrastructure, such power quality disturbances in the SEEDZ area occur regularly.

Ways To Address Power Quality And Reliability

Metrics such as SAEFI and SAIDI broadly define grid reliability, yet data and metrics for measuring power quality on the grid are currently limited and not well understood. A grid-level view of detailed data on power quality events - date, time, magnitude, duration, impact – is essential to addressing and improving power quality. This detailed data pinpoints power quality issues over time, and aids in assessing and deploying the most cost-effective fixes.

A recent EPRI study of power quality revealed that voltage sags and interruptions averaged 18 a year across the U.S. Where incident rates are high and/or where customer impacts are most material, improvements in utility grid infrastructure are necessary to reduce the number and severity of power quality issues. Furthermore, resiliency improvements can be made at customers’ facilities - to better ‘ride through’ such disturbances on the grid, and in turn, reduce impacts these same facilities may have on grid power quality. As summarized in the table below, power quality monitoring, mitigation, and improvements can be made at customer locations, and in grid infrastructure and services.

PQ Important results: Avg voltage sags and interruptions

Establishing A SEEDZ Power Quality Monitoring ‘Portal’

Within the SEEDZ area, several major customers have implemented detailed power quality meters at their facilities’ utility service entries. These meters are providing important benefits, helping customers to pinpoint power quality events, correlate events with equipment malfunctions, optimize equipment placement, and provide a quantified basis for investment in power quality mitigation equipment.

Yet currently, utilities do not generally have visibility to this detailed level of power quality data across their distribution grids. For a customer experiencing an outage or a power quality event, it is difficult to quickly determine if the event was specific to their circuit, substation, or area-wide transmission. And for the utility, it is difficult to quickly assess to what degree a given event was ‘felt’ across the network. When events occur in the SEEDZ area, neighboring customers often engage in social networking and email each other to determine the extent of the problem - in parallel with contacting the utility.

SEEDZ is now in the process of establishing an area-wide power quality monitoring system that will aggregate detailed data from customer meters in the area. The system will collect event data from instrumentation at customers, as well as qualitative input on events and customer impacts. Log in access to the SEEDZ Power Quality Monitoring ‘Portal’ will provide users with an immediate view of recent incidents in the area. It will also provide plots of incidents over time versus various power quality standards such as CBEMA-ITIC or P1668, and on a geographic overlay. And it will provide access to root cause information when determined.

The business case for PQ monitoring Justification for PQ data aquisition

The system aims to facilitate improved power quality and resiliency in the area, incorporate leading smart grid power quality standards, and enable the zone to serve as a model and test bed for grid integration of distributed generation, electric vehicles, and advanced industrial uses.


  • Understanding the Power Quality Environment: Bill Howe, EPRI (slides)
  • Power Quality and the PG&E System: Jerry Hutchison and Frank Arroyo, PG&E (slides)
  • EPRI’s Power Quality Research Program: Bill Howe, EPRI (slides)
  • Local Power Quality Issues and Monitoring Capabilities: Ralph Renne, NetApp/ Paul Niemann, NetApp (slides)
  • Power Quality Metering: Andy Taylor, Applied Power Technologies (slides)
  • Power Quality Economics: Bill Howe, EPRI (slides)
  • Business Case for Measuring Power Quality: Ralphe Renne, NetApp (slides)
  • Managing Power Quality in Data Center Environments: Dennis Symanski, EPRI (slides)
  • Understanding Equipment Sensitivities: Mark Stephens, EPRI (slides)
  • Power Quality Standards, SEMI F47, IEC 61000-4-34: Mark Stephens, EPRI (slides)
  • Embedded Solutions for Improving End-Use System Performance: Mark Stephens (slides)
  • Mult-Level Approaches for Mitigating Power Quality Issues: Bill Howe, EPRI (slides)
  • High-Definition Power Network Simulation and Visualization: Peter Evans, New Power Technologies (slides)
  • Power Quality Impacts and Mitigation: Larry Owens, Silicon Valley Power (slides)