What Is a Compensation Panel?
A compensation panel is an automatic system that balances the reactive power consumption created by inductive loads such as motors, transformers, and ballasts in industrial and commercial facilities using capacitor steps, and keeps the power factor (cosφ) within the 0.98–1.00 range. In Türkiye, TEDAŞ/BEDAŞ imposes a reactive power penalty on facilities with cosφ < 0.98. A compensation panel completely eliminates this penalty, reduces transformer and cable losses, and provides 10–30% overall energy savings. The reactive power relay controller measures the cosφ value several times per second and automatically switches capacitor steps in and out according to the need.
Why Is Reactive Power a Problem?
There are three types of power in the electrical grid:
- Active power (P) – kW: Power that does useful work (motor turns, heat is produced)
- Reactive power (Q) – kVAR: Power that creates a magnetic field and does no work
- Apparent power (S) – kVA: Vector sum of active + reactive (S² = P² + Q²)
Power factor (cosφ) = P / S. As cosφ approaches 1, efficiency increases. Inductive loads (motor, transformer, fluorescent ballast) reduce cosφ to the 0.7–0.85 range. As a result:
- The current drawn from the grid increases → cable and transformer losses grow
- Transformer capacity is filled unnecessarily → new load cannot be connected
- TEDAŞ/BEDAŞ issues penalties → the bill increases by 10–25%
- Panels and cables overheat → service life shortens
How Does Compensation Work?
- The reactive power relay controller (Entes RG3-12C, Mikro DCRG8, ABB RVC) continuously measures cosφ and THD values.
- When cosφ falls below 0.98, it calculates the required reactive power.
- It switches in the appropriately sized capacitor step via a contactor.
- When the load decreases, it automatically switches steps out.
- To extend capacitor life, it changes the step order with a rotation algorithm.
Components of a Compensation Panel
- Capacitor Banks: 2.5 / 5 / 7.5 / 10 / 12.5 / 25 / 50 / 100 kVAR
- Reactive Power Controller: 6–18 steps, RS485 / Modbus communication
- Contactors: Special compensation contactors (with pre-resistors, AC6b)
- Fuse or Circuit Breaker: Separate protection for each step
- Current Transformer (CT): To measure main line current
- Inductance (Reactor/Coil): For harmonic filtering (mandatory if THD > 5%)
- Panel Enclosure: TS EN 61439-2 certified
Detuned (Reactor-Type) Compensation
In facilities with harmonics (frequency-inverter motors, UPS, multiple LED driver loads), a classic compensation panel is insufficient. In a detuned compensation panel, a series reactor (inductance) is connected to the capacitors. This reactor filters the 5th and 7th harmonics and protects the capacitors from resonance. The detuning ratio is generally selected as 7% (189 Hz) or 14% (134 Hz).
Savings Calculation – Sample Application
Facility: 500 kVA transformer, 350 kW load, cosφ 0.75
- Reactive power consumption: Q = P × tan(arccos(0.75)) = 350 × 0.88 = 308 kVAR
- Grid current (without compensation): 350 / (0.75 × 0.4 × √3) = 674 A
- Monthly reactive bill without compensation: ~6,000–12,000 TL
- Annual gain with compensation (cosφ 0.99): 80,000–150,000 TL
- Panel investment: 200 kVAR detuned ≈ 180,000–260,000 TL
- Payback period: 12–24 months
Compensation Panel Installation Process
- Energy analysis: A 7-day measurement determines the active/reactive/harmonic profile.
- Correct capacity calculation: Calculated using Q = P × (tanφ1 - tanφ2).
- Panel design: Detuning requirement, number of steps, IP rating are determined.
- Production and test: Manufacturing with TS EN 61439-2 type testing.
- Installation and commissioning: CT connection, controller settings, step test.
- Performance report: cosφ and savings report with 30 days of monitoring.
DOA Enerji Compensation Panel Manufacturing
DOA Enerji Aydınlatma manufactures classic and detuned compensation panels at its Başakşehir İOSB facilities using Schneider, ABB, Frako, and Iskra products. Free energy analysis, capacity calculation, and 12 months of performance monitoring after commissioning are provided. All panels are TS EN 61439-2 certified and come with a 2-year warranty.
Frequently Asked Questions (FAQ)
Do I really need a compensation panel?
If your facility has inductive loads such as motors, transformers, welding machines, frequency inverters, LED drivers, fluorescent/HID luminaires, and you see a “reactive power consumption charge” line on your bill, you definitely need a compensation panel.
How much energy savings does a compensation panel provide?
It does not directly reduce active consumption; however, it zeros reactive power penalties, reduces cable and transformer losses by 3–7%, and enables more efficient use of transformer capacity. Total bill savings are in the 10–30% range.
What is the difference between detuned and classic compensation?
Classic compensation only corrects reactive power. Detuned (reactor-type) compensation filters harmonics by adding a series reactor to the capacitor and prevents resonance. If THD-V > 5% in the facility, detuned must be preferred; otherwise the capacitors will blow.
How much does a compensation panel cost?
With 2026 prices: a 50 kVAR classic panel is ~85,000–120,000 TL, a 100 kVAR classic is ~150,000–200,000 TL, and a 200 kVAR detuned is ~250,000–380,000 TL. The brand, capacitor type (cylindrical / dry), and detuning selection affect the price.
How is compensation panel maintenance performed?
Every 6 months, thermal imaging inspection, capacitor capacitance measurement, contactor cleaning, and relay setting checks are required. One detailed maintenance per year is recommended. Capacitor life is 50,000–150,000 hours and it should be replaced if swelling/leakage is observed.