Genset paralleling cabinets
- Automatic synchronization: voltage / frequency / phase angle captured automatically, breaker closes only when synchronizing conditions are met
- Load sharing: active power shared proportionally (±5%), reactive power equalized automatically
- Number of units in parallel: 2–8, power ratings may differ (shared in proportion to capacity)
- Protection: reverse power, overcurrent, loss of excitation, over/undervoltage, overspeed trip protection
- Sequence interlock: works with ATS / AMF, on loss of mains the sets start automatically, parallel and take load
Specifications
The table below covers 80% of factory distribution room cases. Anything outside it we can still build — those are engineered items, quoted separately, with an indicative price the same day.
| Type | GGD modular floor-standing cabinet, installed beside the generator sets or centrally in the electrical room |
|---|---|
| Standard sizes (W×D×H) | 800×600×2200 / 1000×800×2200 mm, custom build available |
| Enclosure construction | 2.0 mm cold-rolled carbon steel, control section and power circuit in separate compartments |
| IP rating | IP30 / IP54 (generator room environment) |
| Display panel | Paralleling controller screen: voltage / frequency / power / status of each unit |
| Cable entry | Bottom cable entry for generator sets; busbar output can be tied through to the ATS cabinet |
| Rated voltage | AC 400V, 50 Hz (generator busbar) |
|---|---|
| Number of paralleled units | 2–8 units, mixed ratings allowed (load shared proportionally) |
| Synchronization method | Automatic quasi-synchronization: voltage / frequency / phase angle auto-matched before breaker closing |
| Load sharing | kW shared in proportion to rating (±5%), reactive power automatically balanced (circulating current loop) |
| Protection configuration | Reverse power, overcurrent, loss of excitation, over/undervoltage, overspeed, underfrequency trip |
| Sequence control | Starts and stops generator sets automatically based on load (peak/off-peak strategy configurable) |
| Communication | RS485 / Modbus reporting, interfaces with plant monitoring system |
| Component brands | Paralleling controller (Deep Sea / ComAp, etc.) + Schneider / Chint components |
| 2-unit main/standby paralleling | One running, one standby; on overload the second unit parallels automatically |
|---|---|
| Multi-unit capacity type | Starts and stops generator sets in stages by load for economical peak/off-peak operation |
| Utility + generator, fully automatic | AMF auto start → synchronization and paralleling → load transfer, fully unattended |
| Mixed-rating paralleling | Old and new generator sets of different ratings share load proportionally; extends the life of existing capacity |
| ATS interlocked | Paralleled busbar transfers to/from utility through the ATS; integrated in the electrical room |
| Assembly standard | GB/T 7251.1 / IEC 61439-1 |
|---|---|
| Synchronization verification | Setting and per-unit verification of synchronization conditions (voltage difference / frequency difference / phase angle) and blocking logic |
| Routine tests (every unit) | Insulation resistance, dielectric withstand, and simulated synchronization closing and trip logic |
| Temperature rise | Main circuit terminals ≤70 K |
| Documents with shipment | System diagram, setting tables, paralleling sequence description, BOM, test report |
Five steps to specify your run
A configuration summary is generated as you go. It travels with your inquiry, saving a round of confirmation.
Build details
Systems have been in service for decades, and the failure points are always the same few: poor busbar contact, water ingress at the door seal, high temperature rise in the correction cabinet, and mis-phased outgoing feeders. The six hard rules below are written for exactly these points — every cabinet can be traced to them.
No close on any fault condition
Closing is permitted only when voltage difference, frequency difference and phase angle all fall within limits; any one out of tolerance blocks the close. The inrush current from out-of-sync closing can damage the generator shaft train — this is an iron rule.
Balanced both active and reactive
Active power is shared proportionally through the governor; reactive power is balanced through the excitation cross-current loop — a dual closed-loop design. Output deviation between generators is visible at a glance, preventing one unit from overheating while another runs idle.
Start to on-load in one pass
Mains failure detection → start → warm-up → synchronization → close → on-load. Delays and conditions at each step are set to the generator characteristics and documented in the sequence description shipped with the unit.
Faulty generator drops offline automatically
Any trip — reverse power, loss of excitation, overspeed — disconnects the faulty generator and load transfers automatically to the healthy units. The reliability of a paralleled system shows in how it degrades automatically under fault.
Every unit logic-tested before shipment
Two signal sources simulate the generator and the busbar. Synchronizing capture, closing, load sharing and trip logic are all powered up and run through end to end — verified without touching a real generator.
Every circuit is tagged to its generator set number
Each generator set's incoming, protection and signal circuits are tagged consistently with the set number, so wiring stays straight even across multiple cabinets.
Photos & enclosure construction
Below are photos taken in our own shop — from the complete unit down to the internal busbars and secondary wiring. Every build detail can be checked item by item.
Image key: 01–05 are shop photos (the numbers match the shot list). The line drawing shows the front elevation of the enclosure; dimensions match the specification table above.
Where these cabinets go
These are the routine applications — we can talk scheme and configuration directly. For the industry view, see the industry pages.
Factory standby power
On loss of utility voltage, generators start and parallel automatically — production continues without interruption.
Data centers and equipment rooms
Multi-generator redundancy + ATS for the highest level of supply availability.
Hospitals and industrial parks
Critical loads backed by multiple generators, with staged load pickup.
Mining & Construction Sites
Economical multi-generator operation in areas without utility power.
Events & Emergency Backup Power
Temporary power plants parallel quickly, with flexible capacity expansion.
Expanding an Existing Generator Fleet
Mixed parallel operation of old and new units of different capacities, preserving existing investment.
Commercial terms
Specification dated September 2026; quotations follow this.
| Drawings & design | Free |
| MOQ | 1 unit (5 or more recommended for production) |
| Production lead time | 15-25 days after drawing approval |
| on-time delivery | 98% |
| Warranty | 12 months |
| Loading port | Ningbo / Shanghai, China |
| Component brands | Schneider / ABB / Siemens / Chint |
| Factory visit & dispatch confirmation | Factory visits welcome; finished-cabinet photos and video before dispatch |
| Capacity | 5,800+ units / year |
Documents for your engineering team
Selection manual, outline dimensions and RFQ checklist — for the customer's electrical engineer. All three documents are being organized by product line; download links go live once complete.
Six questions procurement and electrical engineers ask most
Can generators of different capacities and brands be paralleled?
Yes, with conditions: matching voltage and frequency class (400V/50Hz), governor and excitation suitable for parallel operation (electronic governor / AVR), and preferably the same controller platform. Different capacities share load proportionally; for different brands we check the interfaces unit by unit and then issue a solution.
How do I choose between parallel operation and a single larger generator?
Parallel advantages: redundancy (no power loss on a fault), economical staged loading, flexible transport and installation, easy capacity expansion. Single-unit advantages: smaller footprint, simpler system, lower initial cost. Where load fluctuates widely or reliability requirements are strict, paralleling is clearly the better value.
How long does automatic synchronization take?
Typically a few seconds to a few tens of seconds: the controller tracks frequency difference and phase angle and closes the breaker once conditions are met. Manual synchronization takes minutes and often fails — that is exactly why automatic paralleling cabinets exist. Total time for sequential paralleling of multiple units depends on the number of units and warm-up delays, and is stated in the solution.
How is load shared among generators?
Active power (kW) is shared in proportion to generator capacity via the governor closed loop; reactive power (kvar) is equalized automatically via the excitation cross-current loop. Deviation is held within ±5%, preventing overheating and fuel consumption imbalance caused by uneven loading.
What happens if a generator faults?
Protections such as reverse power, loss of excitation and overspeed trip to disconnect the faulty generator automatically, and the remaining generators share the load in proportion to capacity; if load exceeds limits, non-critical circuits are shed by priority. The full degradation strategy is documented in the setting table, and the unit re-parallels automatically after recovery.
Can it connect to plant monitoring?
RS485 / Modbus is standard: operating parameters, parallel status and alarms from each unit are reported to plant monitoring or a remote O&M platform; generator signals such as fuel level and coolant temperature are also connected. This link is what makes unattended generator rooms possible.
Other cabinet types in the same main circuit
Related products use color-block placeholders for now (product photos not yet complete; they will be replaced together). Internal links will be filled in once live URLs are confirmed.
Send us your generator parameters and we configure the paralleling solution to match
Send us your generator parameters (number of units / capacity / brand) and load requirements for a free paralleling solution · quotation within 24 hours. Direct from the source factory, MOQ 1 unit, 15–25 day delivery, 1-year warranty.
ISO 9001:2015 · CE(LVD+EMC) · CQC · IP65
When you write, include: single-line diagram or primary scheme, switch room layout, load list, and component brand requirements. You do not need complete drawings — capacity and cabinet type are enough to start.