Protect power-switching equipment, large electrical assets

Aug. 1, 2013

Many large electric-power consumers feel secure in owning and maintaining high- and medium-voltage transformers and power-switching equipment.

By Mo Rousso

Many large electric-power consumers feel secure in owning and maintaining high- and medium-voltage transformers and power-switching equipment. Once installed, little maintenance is generally required and a system can go largely unnoticed and essentially forgotten for substantial periods of time.

There are risks, however, and the consequences can be severe. Water and wastewater treatment facilities are particularly sensitive to unplanned power interruptions that can result in serious damage to a transformer. And without power, facilities can’t deliver services expected by the public.

Power monitoring can help. Real-time monitoring and alerts of critical power-distribution irregularities can provide early notifications of potential failure, indicate where preventative measures could be taken and prevent serious system damage.

More is needed

But basic monitoring systems alone quite often aren’t enough.

For example, Helio Energy Solutions installed basic energy and power monitoring at a large commercial facility in July 2009. The monitoring system captured utility-meter pulse data recorded at 15-minute intervals. Pulse data provides only kWh energy consumption information (as opposed to all three power phases), and when integrated over time, can provide gross power in kW.

In September 2011, a power system failure of one of two high-voltage power transformers caused a complete facility power interruption and subsequent transformer destruction. The power transformer was one of two original units installed during construction 20 years earlier. Post-failure analysis efforts identified, among other things, the absence of detailed energy and power monitoring as a potential contributor to the unchecked failure. Pulse data from the utility meter is quite limited and could not provide any foresight into the pending system failure.

One result of the catastrophic failure was that power monitoring was made a requirement for transformer re-commissioning. In early 2012, a replacement high-voltage power transformer was installed. Helio Energy Solutions installed advanced monitoring at each power transformer, with detailed one-minute sampling and a comprehensive list of data-monitoring parameters.

How it works

Advanced monitoring is done by inductive type meters capturing a wide range of electrical, energy and power parameters on all three power phases. These parameters — including voltage and current by phase, along with power factor and phase angle — give insight into the health and function of the transformer when evaluated on an ongoing basis.

Helio Energy Solutions’ PredictEnergy is an energy analytics software platform that helps manage energy demand costs, enables cost audits and assessments to drive down process costs, optimizes distributed generation and energy cost-down programs and manages energy costs against unit production or other key-performance indicators.

Power-distribution failure is a hidden risk only vaguely intuited by the many large electrical-power consumers who own and maintain high- and medium-voltage transformers and power-switching equipment. Too often, this type equipment is overlooked in the risk-mitigation process due to its few or non-existent maintenance requirements and lack of visible interaction with facility personnel and site process.

Water and wastewater treatment facilities are particularly sensitive to unplanned power interruption due to the continuous large power draw and importance of uninterrupted service. Monitoring output of these large, expensive assets with inductive meters can mitigate risk through insight into pending equipment failure and the need for preventive maintenance.

Age of analytics

Advanced monitoring and analytics can perform over a wide range of parameters. Most important are 1) line and phase parameters for comparison and 2) power-factor and load-condition parameters. Examples within each category include:

  • Line voltage, power, energy and current
  • Phase level voltage, power and current
  • Power factor
  • Reactive power
  • Apparent power
  • Frequency
  • Temperatures

The combination of data granularity and analytics capability creates a powerful, extendable environment that supports electrical distribution asset and risk management.

Beyond the detailed visibility provided by the inductive meter, a complete set of alarms and alerts enhances the facility maintenance team’s understanding of the asset’s conditions, especially as related to the current energy environment, and in relation to other critical energy components and sources. Alarms identify out-of-tolerance data parameters.

The alarm levels and settings are customizable by the user, allowing filtering of false indications.

Having too much

Many sites are fed by some form of onsite distributed energy generation. Depending on the load distribution and number of transformers, it is possible for the generation system to produce more energy than is consumed by the site on a single transformer.

This can result in auto-disconnects from the generation system even though the overall facility consumption exceeds total energy production.

Analytics can be created to not only present, but also predict this type of pending loss of distributed generation and subsequent harsh loading of the transformers when large power supplies fall off abruptly. Unique power distribution challenges exist frequently, especially at older facilities.

Many wastewater treatment facilities have non-standard power distribution architectures. This takes many forms, such as multiple transformers feeding imbalanced loads with open or closed ties, older-style switchgear and mixed-age equipment. Wastewater treatment facilities vary widely in origin, layout, age and utility infrastructure interface. The customizable capability and data acquisition flexibility of PredictEnergy eliminates having to select a prepackaged system that may work well in some applications but not at all for others.

Mo Rousso is president and CEO of Helio Energy Solutions. Helio Energy Solutions provides analytics services for distributed generation, load monitoring and energy analytics. HelioPower is a full service, licensed and bonded engineering, procurement and construction company.