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.