Power quality and energy efficiency – an innovative approach

October 14th, 2014, Published in Articles: Energize

 

Impact Energy’s leading edge technologies, systematic consulting and engineering approach to identify power quality related consequences reduces losses and sustains real savings for all sectors of power users and power suppliers. Impact Energy is the brand ambassador and exclusive agent for the Elspec product and service portfolio.

Elspec offers a wide range of real-time power quality enhancement systems which optimise power consumption for electrical energy savings. Comprehensive solutions are available for power factor correction, energy savings, voltage support, flicker reduction, current spike reduction, harmonic filtration, reduction of reactive power during large motor startups and many other applications for a variety of dynamic loads.

It is common, widely published knowledge that continuous mining and manufacturing process plants and digital industries are the most vulnerable to power quality (PQ) related disturbances. Of similar significance is the growing awareness of economic losses that supply related entities such as Eskom, IPP’s and municipalities have to account for as part of economic sustainability.

 

Description of change in supply conditions

Effect on equipment

Savings due to reactive current compensation and harmonics reduction
Transformers-   Current reduction-   Harmonics reduction The presence of harmonic current increases the core losses, copper losses and stray-flux losses. These losses consist of “no load losses” and “load losses”.
Cables-    Current reduction-    Harmonics reduction Additional “Ohmic losses” (I2R losses) in the line and neutral conductors.The eddy current, which is generated due to the relative motion of the electromagnetic field and circulating current in a conductor, is the root cause of skin effect.
Capacitors-    Current reduction-    Harmonics reduction Voltage harmonics increases dielectric losses in capacitors and reduction of operational lifetime of PFC capacitors.Resonance and possible catastrophic failures of capacitor bank systems.
Load-   Harmonics reduction (skin effect,
hysteresis, negative sequence
field due to 5th, 11th etc.)
Increased motor currents in individual phases, resulting in heating and copper losses.Other mechanical/electrical issues e.g. torque reductions, cooling fan problems, insulation degradation.Tripping of VSD’s during unbalance conditions.
Saving due to optimal voltage control For non-linear loads, voltage variation due to load variations affect power consumption patterns. Through cycle by cycle reactive energy compensation, voltage is increased and more stable. It is possible to tap down transformers and this has potential energy saving benefit.

Table 1: Typical technical loss (kWh) opportunity considerations.

Network components suffer extra losses, reduced operational efficiency, abnormal tripping, progressive degradation and premature failure because of various power quality anomalies. The long term financial losses as a result of poor power quality are those which are not commonly and easily quantified: production losses, scrap, inferior product quality, rework, additional labour and maintenance costs, increased and frequent sustaining capital investment, etc.

Fig. 1: Elspec's Blackbox device for perfect PQ.

Fig. 1: Elspec’s Blackbox device for perfect PQ.

The innovative and systematic power quality approach

Since energy is supplied on a continuous cycle by cycle basis, it is natural that PQ and loss analyses should be done on a cycle by cycle basis too, to obtain an accurate representation of the performance of a power network.

A formal engagement with Impact Energy on an innovative systematic PQ approach ensures the following key deliverables:

  • Comprehensive power quality study: Using Elspec’s G4K cycle-by-cycle continuous measurement devices and patented PQZIP compression technology, permanent fixed or temporary rental meters.
  • PQ modelling and loss analysis: Through a combination of network parameter modelling and cycle by cycle measurements, Elspec is able to produce highly accurate simulations of system technical losses.
  • PQ solution conceptual offering: Using the measurements taken to determine the primary PQ issues for the site the company is able to determine various solutions for reactive energy compensation, voltage support, motor start, dip ride through and harmonic filtering.
  • Present a loss analysis and business case evaluation placing emphasis on three key aspects of losses: Technical system losses, non-technical production related losses and possible demand (kVA) related savings on the power bill.
  • Obtain approval on designs and prepare for procurement and execution phase.
  • An official report of energy savings after the solution has been implemented.
  • Power quality metering and solution routine reporting and maintenance: A supplementary option to support key personnel in ensuring that benefits and value realised are sustainable.

Contact Sishal Kanaye, Impact Energy, Tel 086 135-7732, sishal@impactenergy.co.za

Related Articles

  • South African Government COVID-19 Corona Virus Resource Portal
  • Ministerial determinations propose 13813 MW of new-build by IPPs, none by Eskom
  • Crunch time for South Africa’s national nuclear company, Necsa
  • Dealing with the elephant in the room that is Eskom…
  • Interview with Minerals & Energy Minister Gwede Mantashe