Powerhouse White Paper
Prepared by Mark Ware
Ohm Energy Technologies
When installed at a Main Distribution Panel (MDP), the Powerhouse levels, boosts, and maintains voltage on all phases of a wye system that uses a neutral. Below are definitions of some terms which are utilized throughout this paper:
- Inductive Load – any load requiring a magnetic field to operate (motors, inductive capacitors, gaseous tube lighting ballasts, transformers, inductive furnaces, fans, relays, solenoids, and chillers). Inductive loads draw a large amount of current (inrush current) when first energized, then decrease after a few cycles to a full-load current.
- Non-Inductive Load (Resistive Load) – any load not containing capacitance or induction such as incandescent lighting or electrical heaters, ovens, burners and toasters. The current instantly attains its steady-state level without first rising to a higher level.
- Reactive Power – the power required to start and maintain a magnetic field in an inductive load. Although reactive power is necessary in operation, it does not provide real work (kW) and is eventually passed through the neutral line to ground. This is measured in kilovolt-amperes-reactive (kVAr).
- Real Power (kW) – the actual work an inductive and resistive load performs, as opposed to kVAr which does not perform actual work. Utilities bill by the KW and sometimes penalize on the amount of kVAr.
- Apparent Power (kVA) – measured in kilovolt-amperes, is the sum of kW + kVAr. It is the total power supplied to an MDP.
- Power Factor – a ratio of real power (kW) and apparent power (kWA): kW/kVA. This is a measure of efficiency. The highest power factor desired is 100% or 1. A number less than 1 indicates inefficiencies within the load. A power factor or 0.80, or 80%, indicates an inefficiency of 20%. Inductive loads lead to a much lower power factor because of the non-working power needed to maintain their magnetic fields. Non-inductive or resistive loads approach 100% efficiency.
Problem: Power, as supplied by the utilities, can be fraught with issues even before the consumer is able to utilize it. These can include blackouts, brownouts, line harmonics due to electromagnetic pulses (EMPs), and issues due to sudden spikes in up-line or downline use. Inside the facilities, power surges, spikes and sags create undue disruption and wear and tear on any motors, chillers, lights, and electrical devices (computers, TVs, outlets, UPS equipment, digital displays, rectifiers, relays, breakers, switches, monitors, etc.). Temporary disruptions (brownouts) or more long-term outages (blackouts) don’t necessarily cause problems or damage when the system is down or off, but most likely create a spike as well as sages when suddenly energized or turned on. This alone is the greatest cause of equipment failure.
Low power factor creates more heat for the inductive load because more current (heat) is needed to make up for the inefficiencies of the load. Even though the damage can occur over a longer period of time, excessive heat, in the form of current is detrimental and destructive to motors. Higher power factor will help with efficiency and increase the longevity of motors by reducing the heat (current) greatly.
Harmonics occur when voltage and current are not in phase with one another in relationship to their respective sine waves. Measured as total harmonic distortion (THD), harmonics are merely a byproduct of nonlinear load. Examples of nonlinear loads are battery chargers, adaptors, fluorescent lamps (because of the choke coil), LEDs, electronic ballasts, variable frequency drives (VFDs), rectifiers, uninterruptible power supply (UPS), switching mode power supplies (SMPS), photocopiers, personal computers, laser printers, and fax machines. However, in a linear load, both voltage and current follow one another without distortion to their pure sine waves. Examples of linear loads are resistive heaters, incandescent lamps, and constant speed induction and synchronous motors.
Effects: The consumer ultimately pays the price in many ways:
- Most utilities penalize commercial users who operate with low power factor (usually under 0.9) in the form of demand charges. If it is not labeled as such on a power bill, this may be disguised as a “fee”.
- Maintenance cost of equipment can account for a company’s greatest expense. Reduction of heat (current) and higher efficiency (power factor) can reduce or significantly defer maintenance costs.
- Most power systems can accommodate a certain level of harmonic currents but will experience problems when harmonics become a significant component of the overall load. As these higher frequency harmonic currents flow through the power system, they can cause a plethora of problems, including:
- Communication errors
- Overheating and damage to hardware
- Overheating of electrical distribution equipment (cables, transformers, standby generators, etc.)
- High voltages and circulating currents caused by harmonic resonance
- Equipment malfunctions due to excessive voltage distortion
- Increased internal energy losses in connected equipment causing component failure and shortened life span
- False tripping of circuit breakers
- Metering errors
- Fires in wiring and distribution systems
- Generator failures
- Lower system power factor, resulting in penalties on monthly utility bills
Solution: The Powerhouse addresses these issues through its use of a patented coupling of electronic components working in concert to capture and recycle reactive power (kVAr) for its reuse. Its unique wiring configuration (Patent #8971007) allows these components to redirect the kVAr to either a capacitive or distributive function as needed within a facility’s power grid. An array of 18 Metal Oxide Varistors (MOVs), each rated at 50 kA, act as surge arresters through a series of internal diodes and resistors. The Powerhouse’s patented wiring configuration allows the MOVs to redirect the many spikes in voltage a facility experiences on a daily basis to a series of fluid-filled capacitors for eventual upsurges in power consumption within a facility. Additionally, the wiring configuration allows for the neutral to be utilized as a secondary power source and is connected inside the Powerhouse so that it can be redirected in a capacitive or distributive function. In this way, the Powerhouse treats the neutral as a “phase D” within a three-phase system, it is for this reason alone that the Powerhouse can only operate within a wye and not a delta system, since the delta does not use a neutral. Also, a delta system generally has a “high leg”, making it impractical, if not impossible, to balance voltage between the phases. The constant and consistent “back and forth” between the MOVs and the capacitors keeps the voltage between the phases boosted, leveled and maintained at all times no matter the load, sudden or otherwise, within a facility’s grid. Similarly, the Powerhouse protects against spikes or surges when the grid is suddenly energized after a power brownout of blackout. For added protection, a secondary surge protector within the Powerhouse protects the grid for up to 50,000 volts.
When the neutral is utilized within the Powerhouse, a unique effect occurs. All values for kW, kWh, kVA, Amperes and kVAr are lowered in a pronounced way. Conversely, power factor increases to typically between 0.95 and 0.99, and voltage increases and remains level in all phases. These effects are confirmed by repeated on/off power logger data tests, and in various independent studies performed by General Electric, Applied Research Laboratories, the Department of Defense and the Department of Energy.
Power Factor Correction
Whitby Hydro Energy Services Corp. Power Factor Correction at the Residential Level – Pilot Project
Report to the LDC Tomorrow Fund
September 12, 2005
In December of 2004 Whitby Hydro applied for funding from the EDA Tomorrow Fund to carry
out a pilot project to determine the impact of installing capacitors at residential homes on system
capacitance and generation requirements.
The study involved 31 homes within Whitby Hydro’s distribution territory. The houses selected
were located in a new residential neighborhood and were consistent in size, age and type of
For the pilot, a bench mark had to be established for the loading of each transformer. The three
transformers where metered for a two month period prior to the installation of the capacitors.
The information gathered included KW, KVAR, volts and amps. Once the benchmark was
established homes fed from two of the transformers where equipped with capacitors providing
3.34 KVAR into their distribution panel. Readings at the transformer continued for an
additional two month period after the units were installed in the homes. In addition two homes
where equipped with metering devices that allowed the measurement of power factor.
The information gathered allowed analysis to be carried out to determine if the additional
capacitance improved power factor at the home as well as at the transformer.
Power Factor at the transformer was the first value to be analyzed. KW and KVAR was
measured at 15 minute intervals for the pilot period (Appendix G). This information was used to
determine monthly power factors and other related billing determinants at the transformer.
The peak Power Factor each month was as follows:
March April May June July
(PF) (PF) (PF) (PF) (PF)
TX5545 (BM) 96.6 96.1 95.1 92.7 93.0
X5554 98.4 98.8 99.9 99.1 99.9
TX5547 97.9 98.5 98.3 97.1 95.7
(Note: BM is the bench mark transformer of which capacitance was not added)
During the study it was quickly realized that although the study group was selected for its
consistency, variances in ON and OFF-peak Power Factor clearly indicated that there was little
or no consistency on how or when motor loads were used. Even though an attempt was made to
pick homes with similar characteristics there was enough variance in how and when motor loads
where used to cause inconsistency between the transformers. This made it difficult to determine
the full effect that the added capacitance had on Power Factor at the transformer. However,
based on the fact that KW and KVAR were being measured it was easy to see the impact the
added capacitance had on KVAR at the transformer. Also because KVAR is a factor when
determining generation requirements, this unit of measurement would allowed us to determine
the impact on provincial generation.
The improvements in KVAR was as follows:
March April May June July
(KVAR) (KVAR) (KVAR) (KVAR) (KVAR)
TX5545 (BM) 4.2041 3.3670 3.0253 7.1944 7.5343
TX5554 2.3756 2.3999 -.9916 -4.3036 -4.0268
TX5547 3.1778 2.6754 .9480 3.0449 2.9364
To further verify the impact of the capacitance on power factor two homes where measured. .
These homes where fitted with capacitors that would turn on and off on twenty four hour cycles
to show day to day comparison on power factor. Typically, the average power factor when the
units where off was 87%. When the units were turned on the power factor was over 99%.
To get a real understanding of positive impact power factor correction has on generation costs
benefit analysis was carried out to see if such a project would make sense on mass. Four
assumptions where used in this analysis:
1. a typical home has a 5kW demand
2. the cost of new generation is about $1,000,000 an MVA
3. a typical homes power factor is improved from 87% to 99% when 3.34 KVAR of
capacitance is added
4. the cost of the Power Correction units is $450,000 installed
With an example of 1000 homes each using the above information, the generation requirement
would be 5.75MVA (5kW/.87PF x 1000). By installing capacitance at the residential level the
requirement of the generator for the 1000 homes would now only be 5.05MVA (5kW/.99PF X
1000) or 700 KVA less.
Therefore the cost to generate 700 KVA would be $700,000 (.700MVA X $1,000,000). The cost
to supply and install capacitance at the residential level to free up the same amount of
capacitance would be $450,000. The environment and health costs associated with the
generation of electricity are also removed making the economics even stronger.
The pilot project showed that the installation of capacitors at the residential level is a viable option in freeing up capacitance within the province is deployed on mass. The savings can also be achieved without having the customer drastically changing their lifestyle.