Power factor correction cabinets
- Control: power factor controller (auto / manual / off), target cosφ configurable
- Switching: 4–10 capacitor stages, contactor switching (standard) or thyristor (rapidly fluctuating loads)
- Reactors: 7% (suppresses 5th-order harmonics and above) / 14% (where 3rd-order harmonics are prominent), optional
- Discharge: discharge device on each stage, residual voltage below 50 V within 3 minutes of power-off
- Protection: overvoltage, undervoltage, harmonic overcurrent and temperature protection; ventilated heat dissipation inside the cabinet
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 | GGJ floor-standing cabinet, coupled in parallel with GGD (busbars run through between cabinets) |
|---|---|
| Standard sizes (W×D×H) | 800×600×2200 / 1000×600×2200 mm, custom builds available |
| Enclosure construction | 2.0 mm cold-rolled carbon steel, top exhaust + bottom intake cooling duct |
| IP rating | IP30 (electrical room) / IP54 optional |
| Safety | Capacitor banks in separate compartments or divided by barriers, so a fault or rupture cannot affect adjacent compartments |
| Cable entry | Bottom busbar entry (continuous with the main cabinet); busbar trunking can be added on top |
| Rated voltage | AC 380V / 400V, 50 Hz |
|---|---|
| Compensation capacity | Estimated at 20%–40% of transformer capacity; final sizing confirmed against the load schedule |
| Controller | Automatic power factor controller (target cosφ, switching delay and thresholds configurable) |
| Capacitors | Self-healing low-voltage parallel capacitors, in 4–10 switched groups |
| Switching method | Contactor switching (standard) / thyristor switches (for frequent load fluctuation) |
| Series reactor | 7% (5th harmonic dominant) / 14% (3rd harmonic prominent), selected per harmonic survey |
| Discharging | Discharge device on each group; residual voltage ≤50 V within 3 min after disconnection |
| Protection | Overvoltage / undervoltage, harmonic overcurrent, cabinet temperature interlocked with fans |
| Component brands | Chint / Schneider / ABB plus specialist capacitor components; customer-specified brands supported |
| GGD parallel standard type | Incoming + metering + compensation cabinets in parallel — standard fit for factory electrical rooms |
|---|---|
| Standalone compensation type | Compensation cabinet added to an existing electrical room, busbar T-connected |
| Harmonic suppression type | For VFD / rectifier loads, with 7% / 14% reactors fitted throughout |
| Phase-wise + common compensation | Phase-wise compensation for unbalanced three-phase loads (combined common + phase-wise) |
| Dynamic compensation type | Thyristor fast switching for fluctuating loads (welders / frequent motor starts and stops) |
| Assembly standard | GB/T 7251.1 / IEC 61439-1; capacitors and reactors meet component standards such as GB/T 12747 |
|---|---|
| Switching verification | Automatic switching logic verified cabinet by cabinet (simulating low cosφ and stepping in groups) |
| Discharge verification | Discharge time measured for each group; below 50 V within ≤3 min |
| Routine tests (every unit) | Insulation resistance, dielectric withstand, and powered interlock testing of controller switching |
| Documents with shipment | System diagram, compensation capacity calculation, terminal schedule, 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.
Calculate first, switch later — no guesswork
Compensation capacity is calculated from the load schedule (motor ratings / duty cycle / existing cosφ), and the calculation sheet ships with the cabinet; how many steps and how many kvar per step are documented, not tuned on site.
Fine step resolution for switching
Group steps are sized to the largest load swing (typical 1:2:2:4 step ratio), so switching is not a hard hit — inrush and voltage flicker stay within limits.
Reactors selected from data
Where VFDs, rectifiers or welders are present, run a harmonic survey before choosing 7% or 14% reactors: a mismatched reactor will at best burn out capacitors on overcurrent and at worst amplify harmonics, making the power bill worse.
No risk during maintenance
Each group has its own discharge device with measured discharge time: residual voltage drops below 50 V within 3 minutes, so a technician opening the cabinet door is not exposed to stored charge — this is recorded in the test report.
A capacitor fault stays contained
Even self-healing capacitors can bulge and fail, so group dividers plus top exhaust isolate the fault to a single group instead of the whole cabinet.
Bolts up to GGD sections
When paralleled with GGD, the inter-cabinet busbar is prefabricated continuous at the factory and bolted on site; busbar cross-section matches the main cabinet — no downgrade.
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 power distribution room
A standard combination paralleled with GGD, with direct savings on power factor adjustment charges.
Motor-dense workshop
Compensation for pump and fan groups, cutting line losses.
VFD-heavy environment
7% reactors plus filtering, preventing harmonic amplification.
Welders and impact loads
Thyristor dynamic switching that tracks fluctuating loads.
Commercial building distribution
Compensation for inductive elevator and HVAC loads, optimizing property power bills.
Retrofit of an existing distribution room
Add a compensation cabinet or replace the internals of the old cabinet, tied in by busbar T-connection.
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
How is compensation capacity calculated?
Rule of thumb: 20%–40% of transformer capacity (take the upper end where motors and inductive loads are heavy). For a precise figure, work from the load list: the difference between target cosφ (0.9–0.95) and existing cosφ × maximum active load. Send us the load list and we will produce the calculation sheet — free of charge.
Why does the power bill depend on power factor?
Under China's two-part tariff, industrial users have their bill adjusted by power factor: 0.9 is the baseline, below it you pay a surcharge, above it you get a rebate (in some regions capped at 0.95). A compensation cabinet often pays for itself within a year through that adjustment alone; the local utility's assessment rules can be checked in the regional tariff document.
Do I need series reactors?
It depends on the harmonic sources: where VFDs, UPS systems, rectifiers or induction furnaces are present, harmonics will resonate in parallel with the capacitors and be amplified, so reactors are mandatory (choose 7% where the 5th harmonic dominates, 14% where the 3rd is prominent); on sites that are mainly resistive, they can be omitted. If you are unsure, run a harmonic survey first — we do not sell reactors blindly.
Contactor or thyristor switching?
Steady loads (a few dozen switching operations a day or fewer): contactor switching, cheaper and durable. Loads that fluctuate frequently (banks of welders, motors started and stopped often): thyristor zero-crossing switching, millisecond response with no inrush, but roughly double the cost. Choose by switching frequency, not by squeezing the budget.
How long do capacitors last?
Self-healing capacitors are designed for roughly 10 years (ambient temperature and harmonics have a major effect): overheating and harmonic overcurrent are the two main killers, so cabinet heat dissipation and reactor selection directly determine service life. Once a capacitor bulges or loses more than 20% of its capacitance, it should be replaced; the controller reading each group's status is the most direct indicator.
Can it be bolted to existing GGD sections?
Yes: the enclosure dimensions match the GGD module, the busbar runs continuous and is bolted on site; a standalone add-on tied in by busbar T-connection is also supported. Send us photos of the existing distribution room and the busbar specifications, and we will produce the connection plan.
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 load list and we will provide the power factor correction calculation free of charge
Send us your load list or transformer capacity and we will provide the required compensation capacity calculation and grouping plan free of charge · 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.