Okay, I've reviewed the PDF you attached. Your concern about the significant difference between kW (kilowatts - real power) and kVA (kilovolt-amperes - apparent power) is valid, particularly when it changes with the load and ambient temperature. This difference is directly related to the power factor.Here's a breakdown of why this is concerning and potential causes

Understanding the Relationship: Power Factor
kVA is the total power supplied to the circuit, including both real power (used to do work) and reactive power (stored in and released by inductive or capacitive elements). kW is the real power consumed by the load, doing actual work. Power Factor (PF) = kW / kVA A power factor of 1.0 (or 100%) means that all the power supplied is being used effectively. A lower power factor (e.g., 0.7) means a significant portion of the supplied power is circulating in the system as reactive power and not doing useful work.

Why Low Power Factor Matters



Increased Current

For a given amount of real power (kW) needed by the load, a lower power factor requires a higher current to be drawn from the supply. This increased current leads to:

Increased I²R losses

Higher current flowing through conductors (wires, transformers) results in greater energy loss as heat (I²R losses), reducing overall efficiency.

Voltage Drop

Increased current flowing through the impedance of the wiring and transformers causes a greater voltage drop. This is likely what your client is experiencing.

Overloading Equipment

Transformers and conductors can be overloaded even if the actual power being used (kW) is within their rating, because they must carry the full apparent power (kVA).

Utility Penalties

Many utilities charge commercial customers a penalty for low power factor because it burdens their system.

Possible Causes for the Observed Behavior (Large kW/kVA Gap and Temperature Dependence)

Based on your observations and the age of the building, here are some likely culprits, along with why they might be temperature-dependent:1.

Inductive Loads Dominated by Older Equipment



Old Fluorescent Lighting (with magnetic ballasts)

These are notorious for low power factor (typically 0.5 to 0.6). As temperatures decrease, the performance of magnetic ballasts can degrade further, worsening the power factor.

Older Motors (Uncorrected)

Induction motors (pumps, fans, HVAC equipment) are inherently inductive loads. Older motors tend to have lower power factors than more modern, energy-efficient motors. Motor efficiency can also decrease with temperature, indirectly impacting power factor.

Older Transformers

Although generally not a major source of reactive power, older, less efficient transformers can contribute, especially when heavily loaded. Efficiency decreases as temperatures increase.2.

Uncorrected Power Factor



Lack of Power Factor Correction Capacitors

If the building doesn't have power factor correction capacitors installed (either at individual loads or centrally at the service entrance), the inductive loads will draw a large amount of reactive power, leading to a low power factor.

Improperly Sized or Failing Capacitors

If capacitors are present, they might be incorrectly sized for the load, or they may have aged and lost their capacitance, rendering them less effective. Capacitance is temperature-dependent.3.

Harmonics



Non-Linear Loads

Electronic devices such as computers, LED lighting, and variable frequency drives (VFDs) can introduce harmonic currents into the system. Harmonics distort the voltage and current waveforms, which can lower the power factor. Harmonics can be difficult to mitigate and require specialized analysis and equipment.4.

Transformer Loading and Efficiency



Lightly Loaded Transformers

Transformers operate most efficiently near their rated capacity. When lightly loaded, their reactive power consumption can become a more significant proportion of the total power, worsening the power factor.

Overloaded Transformers

Overloaded transformers can experience increased core losses and increased reactive power consumption, also contributing to a lower power factor.5.

Loose Connections and Wiring Issues

Loose connections, corroded contacts, and general degradation of the electrical system can increase impedance, contributing to voltage drop and potentially impacting power factor indirectly. These issues can be temperature-sensitive, as expansion and contraction can exacerbate the problems.

Why Temperature Dependence? Ballast Performance

As mentioned above, magnetic ballasts in older fluorescent lighting are very temperature-sensitive.

Capacitor Performance

Capacitors used for power factor correction have capacitance values that can change with temperature.

Motor Efficiency

The efficiency of electric motors is influenced by temperature. Higher temperatures can reduce efficiency, leading to increased current draw and potentially a lower power factor.

Conductor Resistance

The resistance of conductors increases with temperature, leading to higher voltage drops.

Next Steps (Field Investigation and Testing)

To pinpoint the exact cause and implement effective solutions, you need to conduct thorough on-site testing. Here's what I recommend:1.

Power Quality Analysis

Use a power quality analyzer to measure: kW, kVA, Power Factor (PF) Voltage and Current Harmonics (THD - Total Harmonic Distortion) Voltage Unbalance Record these parameters over time, especially during periods of peak load and when the low power factor is most pronounced. Analyze the data to identify the sources of reactive power and harmonics.2.

Load Survey

Identify and categorize the types of loads connected to the electrical system. Pay close attention to the age and type of lighting (fluorescent with magnetic ballasts vs. LEDs), motors (induction motors vs. newer, more efficient types), and electronic equipment. Determine the power factor of individual loads if possible (clamp-on ammeter and voltmeter can give you an approximation).3.

Transformer Assessment

Measure the voltage and current on both the primary and secondary sides of each major transformer. Calculate the transformer loading to determine if any transformers are overloaded or underloaded. Check transformer nameplate information for voltage and kVA ratings.4.

Capacitor Bank Inspection (if present)

Visually inspect the capacitors for signs of damage (bulging, leakage). Measure the capacitance of each capacitor using a capacitance meter. Compare the measured values to the nameplate values. Check the connections to the capacitors to ensure they are tight and corrosion-free.5.

Thermal Imaging

Use a thermal imaging camera to scan electrical panels, transformers, and conductors for hotspots. Hotspots can indicate loose connections, overloaded circuits, or failing equipment.

Potential Solutions

Based on the findings of your investigation, you can implement the following solutions:

Power Factor Correction

Install power factor correction capacitors to compensate for the inductive reactance of the loads. Capacitors can be installed at individual loads, at distribution panels, or at the service entrance.

Replace Inefficient Equipment

Replace old fluorescent lighting with LEDs, which have a much higher power factor and are more energy-efficient. Replace older, less efficient motors with newer, high-efficiency models.

Harmonic Mitigation

Install harmonic filters to reduce the levels of harmonic currents in the system.

Transformer Optimization

Reconfigure the transformer connections to balance the load across the phases. Replace overloaded transformers with larger units. Consider using energy-efficient transformers.

Wiring and Connections

Repair or replace any damaged or loose wiring and connections.

Load Balancing

Ensure that the load is evenly distributed across the three phases of the electrical system.

Key Takeaways: A large gap between kW and kVA indicates a low power factor. Low power factor leads to increased current, voltage drop, and energy losses. Temperature dependence suggests specific problems with ballasts, capacitors, or equipment efficiency.* Thorough field investigation and testing are essential to pinpoint the root cause and implement effective solutions.I hope this detailed analysis helps you in your investigation. Let me know if you have any more questions or want to discuss specific findings from your field testing! Flag for review