## TL;DR

Sizing a 750 kVA standby diesel generator for a UAE oilfield camp requires balancing extreme environmental conditions with complex inductive loads. In the UAE, ambient temperatures often exceed 50 °C with high humidity, necessitating a significant derating of the alternator and engine performance—a 750 kVA unit at STP may only provide 600-650 kVA of usable power in July. The procurement process must account for the camp’s peak load, typically dominated by HVAC systems and industrial kitchen equipment. Key steps include applying a 1.25 safety margin to the running kW and calculating the surge current of the largest motor (often a fire pump or AC compressor) to prevent voltage dips that could trip sensitive electronics. Compliance with ISO 8528 and local regulations from DEWA, ADDC, or Dubai Civil Defence for fuel storage and emissions is mandatory. A well-sized 750 kVA unit ensures operational continuity for staff housing and critical communications without the risk of wet stacking during low-load periods or overheating during peak summer demand.

## Calculating the standby diesel generator duty point

To determine if a 750 kVA generator is sufficient, the procurement manager must perform a total load analysis. First, sum the continuous running kW of all camp equipment (lighting, HVAC, water treatment). Convert this to kVA by dividing by the power factor (typically 0.8). For example, a 480 kW load equals 600 kVA. Then, apply a safety factor of 1.25: 600 kVA × 1.25 = 750 kVA. However, the sizing is not complete until you account for the largest motor's starting surge. A Direct-On-Line (DOL) motor can draw 6–7 times its rated current during startup. If the camp has a 50 kW motor, the surge could be 350 kW. The generator must have sufficient transient response to keep the voltage drop below 15-20%, as per ISO 8528-5 G2/G3 classes. For oilfield camps in the UAE, the sizing must also include a 10-15% altitude and temperature derating factor if the unit is not specifically designed with a 50 °C tropical radiator and a high-ambient alternator.

## Standards and the UAE codes that apply

Generator installations in the UAE must adhere to strict federal and emirate-level codes. ISO 8528 is the primary international standard for reciprocating internal combustion engine-driven alternating current generating sets, defining performance classes (G1 to G4). IEC 60034 governs the rotating electrical machines (the alternator). Locally, DEWA (Dubai) and ADDC/AADC (Abu Dhabi) have specific requirements for the Point of Connection and earthing systems. If the generator supports life-safety systems, NFPA 110 is often referenced for emergency power supply systems. Dubai Civil Defence (DCD) and its counterparts in other emirates regulate the fuel tank installation, requiring double-walled tanks and specific fire suppression systems. Furthermore, ESMA (Emirates Authority for Standardization and Metrology) may require specific certifications for equipment imported into the UAE, ensuring it meets the harsh environmental requirements of the Rub' al Khali or coastal oilfields.

## Common procurement traps for oilfield camps

The most dangerous trap in the UAE is ignoring ambient derating. Many manufacturers quote ratings at 25 °C; at 50 °C, the air is less dense, reducing cooling efficiency and engine oxygen intake. Another trap is "wet stacking," which occurs when a 750 kVA generator runs at less than 30% capacity for extended periods. This leads to unburnt fuel in the exhaust, damaging the engine. If the night-time load is only 100 kVA, the 750 kVA unit will suffer; a split-set (2 x 400 kVA) might be better. Harmonics are also a concern; if the camp uses many Variable Frequency Drives (VFDs) or UPS systems, the non-linear loads can cause alternator overheating. Ensure the procurement specification includes a Permanent Magnet Generator (PMG) excitation system to provide better motor starting and immunity to harmonic distortion. Lastly, ensure the fuel system is rated for high-sulphur diesel if the site is remote.

## Worked example for a 750 kVA oilfield camp

Let’s size a unit for a 200-man camp in the Western Region of Abu Dhabi.

1. **Base Load Calculation**: HVAC (300 kW) + Lighting/Kitchen (100 kW) + Water Treatment (50 kW) = 450 kW Total Running Load.

2. **KVA Conversion**: 450 kW / 0.8 PF = 562.5 kVA.

3. **Safety Margin**: 562.5 kVA × 1.25 = 703.1 kVA.

4. **Motor Starting Check**: Largest motor is a 45 kW pump (DOL start). Starting kVA ≈ 45 kW × 6 = 270 kVA.

5. **Total Transient Requirement**: Most 750 kVA generators can handle a 270 kVA step load while maintaining voltage within G2 limits.

6. **Environmental Derating**: At 50 °C, a standard 750 kVA unit may derate by 10%. We need a unit rated for 825 kVA at STP to guarantee 750 kVA in the UAE summer.

**Recommendation**: Specify a 750 kVA (Prime Rating) or 825 kVA (Standby Rating) unit with a 50 °C radiator and PMG excitation.

### What is the difference between Standby, Prime, and Continuous ratings?

### Does DEWA require a specific breaker for 750 kVA generators?

### How much fuel storage is required for 24-hour operation of a 750 kVA set?

How to size a 750 kVA standby diesel generator for a UAE oilfield camp