EN
HXGN-24 Fixed-Type Ring Main Unit - 24kV Compact Switchgear
- Overview
- Applications
- Technical Data
- Services
- Quality Control
- Recommended Products
HXGN-24 Fixed-Type Ring Main Unit - 24kV Compact Switchgear
HXGN-24 extends the fixed-type ring main platform to 24kV, serving secondary distribution on 20kV and 22kV networks. Like the 12kV version it combines a three-position load break switch, earthing switch and optional HV fuse protection in a compact air-insulated metal-enclosed cabinet, but with the larger clearances and higher insulation level that 24kV service demands.
WHY THE 24kV CLASS EXISTS
A 24kV panel is not a re-badged 12kV cabinet. Power-frequency withstand rises to 50kV and lightning impulse withstand to 125kV peak, requiring greater phase-to-phase and phase-to-earth clearances, physically larger epoxy components and a taller enclosure. This matters commercially because 20kV and 22kV distribution is expanding: Eastern European utilities operate 20kV as a mainstream distribution voltage, and Gulf networks in the UAE and Qatar run 22kV alongside 11kV. Specifying a 12kV unit for these networks is not a cost saving, it is a dielectric failure waiting to happen.
THREE-POSITION SWITCHING AND RING OPERATION
The load break switch provides Closed, Open and Earthed positions from a single interlocked mechanism, giving a visible positive earth before cable work with no separate earthing device. In ring configuration, two units carry the incoming and outgoing ring cables while a third feeds the local transformer, so a cable fault is isolated by reconfiguring the ring rather than by losing supply to every downstream customer.
AIR INSULATION AND THE F-GAS QUESTION
HXGN-24 is air insulated. For EU and Eastern European buyers this is increasingly a procurement advantage rather than a technical compromise: there is no SF6 inventory to report, no leakage monitoring obligation and no end-of-life gas recovery requirement. Where the installation environment is severe - coastal salt fog, desert dust, flood risk or below-grade siting - a sealed gas-insulated unit remains the more durable choice and should be specified instead.
ENVIRONMENTAL ADAPTATION
IP3X is standard with IP4X available. Gulf installations receive a derating assessment against actual 50-55 C ambient rather than the IEC +40 C reference. CIS supply is available in GOST 15150 climatic versions with anti-condensation heating and cold-rated lubricant.
PRIMARY APPLICATIONS
- Secondary distribution on 20kV Eastern European networks - Poland, Romania, Bulgaria, Hungary, Serbia.
- 22kV distribution in the UAE, Qatar and the wider Gulf region.
- Compact and packaged substations for residential, commercial and light industrial developments fed at 20kV or 22kV.
- Urban ring feeder switching points on 20kV and 22kV cable networks.
- Industrial estate and free-zone internal distribution.
- Renewable generation collection at 22kV, where the higher collection voltage reduces cable losses across large solar and wind sites.
- Transformer protection via load break switch and HV fuse combination.
- Municipal reticulation, including South African 22kV networks.
TYPICAL CONFIGURATIONS
Two-unit ring in / ring out; three-unit with transformer feeder; four-unit and above with additional feeders or metering. Field-extensible as the network develops.
REGIONAL FIT
- Eastern Europe: mainstream 20kV distribution, supplied to EN 62271-200. Air insulation avoids F-Gas obligations.
- UAE and Qatar: 22kV distribution, subject to DEWA and KAHRAMAA material approval.
- Russia and CIS: 20kV urban networks, GOST R certified with climatic version marking.
- Africa: 22kV municipal and industrial reticulation, notably South Africa.
NOT SUITABLE FOR
33kV and 35kV networks - specify the 40.5kV class. Applications needing full short-circuit breaking on every feeder without fuses - specify a withdrawable breaker panel. Severe environments with flooding, heavy dust or salt fog - specify a sealed gas-insulated unit. Networks at 10kV or 11kV, where HXGN-12 is correct and more economical.
TECHNICAL DATA - HXGN-24
Compliance: IEC 62271-200, IEC 62271-103
| Category | Item | Parameter Details |
| ELECTRICAL RATINGS | Rated voltage | 24 kV |
| Rated frequency | 50 Hz / 60 Hz | |
| Rated power-frequency withstand voltage (1 min) | 50 kV | |
| Rated lightning impulse withstand voltage (BIL) | 125 kV peak | |
| Rated normal current | 630 A | |
| Rated short-time withstand current | 20 kA for 4 s | |
| Rated short-circuit making current | 50 kA peak | |
| Load break switch breaking capacity | 630 A | |
| Fuse-protected transformer circuit breaking | up to 31.5 kA with HV fuse | |
| CONSTRUCTION | Insulation medium | air |
| Switch type | three-position load break switch - Closed / Open / Earthed | |
| Protection degree | IP3X standard; IP4X optional | |
| Enclosure | cold-rolled steel, powder coated RAL 7035 | |
| Busbar material | copper | |
| Cable connection | bottom entry, bolted lug or separable connector | |
| Operation | manual lever standard; motorised AC/DC 110V or 220V optional | |
| Interlocking | mechanical, enforcing switch-earth-door sequence | |
| DIMENSIONS | Unit width | 500 mm / 600 mm depending on function |
| Unit height | 1800 mm / 2000 mm | |
| Unit depth | 1100 mm / 1200 mm | |
| Approximate weight | 300-450 kg per unit | |
| SERVICE CONDITIONS | Ambient temperature | -10 ℃ to +40 ℃ per IEC; up to +55 ℃ with derating |
| Altitude | up to 1000 m standard; up to 2000 m on request | |
| Relative humidity | daily average not exceeding 95% |
OPTIONS
HV fuse protection for transformer circuits | motorised operating mechanism | anti-condensation heater | cable fault passage indicator | voltage presence indicator | IP4X upgrade | GOST 15150 climatic version | surge arrester provision | extensible busbar coupling
PRE-SALES ENGINEERING
- Single-line diagram review and panel schedule development from your load list.
- Equipment selection verified against destination grid: 11kV/13.8kV/22kV/33kV (Middle East, Africa), 6kV/10kV/35kV (Russia & CIS), 10kV/20kV/35kV (Eastern Europe). Saudi Arabian projects are designed and verified at 60Hz.
- Ambient derating study. IEC 62271-1 rates equipment at +40 C; we recalculate continuous current for 50-55 C Gulf conditions or supply GOST 15150 climatic versions (UHL1 to -60 C) for CIS sites.
- Short-circuit and protection coordination check against your upstream fault level.
- 2D/3D general arrangement drawings, foundation and cable-entry layouts before production release.
MARKET ACCESS AND DOCUMENTATION
We prepare the technical dossier behind the approval, which is normally the longest item on the project critical path:
- Saudi Arabia: SASO / SABER product certificate (PCoC) and per-shipment certificate (SCoC); SEC material approval support and witnessed factory acceptance testing.
- UAE / Qatar / Kuwait / Oman: documentation packs for DEWA supplier registration, KAHRAMAA material approval, MEW submission and Oman DCRP product approval (mandatory since 2018).
- Iraq: ICIGI certificate of conformity via COSQC-appointed inspection bodies.
- Africa: SONCAP PC and SC for Nigeria, KEBS PVoC (Route A/B/C) for Kenya, TBS / UNBS / GSA certificates elsewhere. Pre-shipment inspection and container sealing coordinated with the appointed agency.
- Russia & CIS: GOST R certification for medium voltage equipment, with EAEU authorised-representative support.
Note that first-time utility approval typically takes 2-12 months depending on the authority. Start this in parallel with order placement, not after.
FACTORY ACCEPTANCE AND DELIVERY
- Routine testing on every panel per IEC 62271-200: power-frequency withstand, main-circuit resistance, mechanical operation, interlock verification, auxiliary circuit function.
- Customer or third-party witnessed FAT (SGS, BV, TUV, Intertek) available on request. Saudi SEC projects require SEC-engineer witnessed FAT.
- Seaworthy export packing: plywood case, desiccant, moisture barrier, shock and tilt indicators for MV assemblies.
- Documentation set: test reports, type-test certificates, GA and schematic drawings, O&M manual, spare parts list, packing list. Manuals available in English, Russian, French and Arabic.
AFTER-SALES
- Commissioning supervision and on-site installation guidance, remote or by engineer dispatch.
- Operator and maintenance training, on-site or online.
- Recommended two-year spare parts list quoted with the order - the single most effective way to avoid extended outages in markets where local spares are unavailable.
- Technical response within 24 hours; consumable spares (contacts, insulators, coils, mechanisms) held in stock for fast dispatch.
- Warranty: 18 months from delivery or 12 months from commissioning, whichever expires first. Extended terms negotiable for framework agreements.
DESIGN VERIFICATION AND TYPE TESTING
- Type tested to IEC 62271-200 for AC metal-enclosed switchgear: power-frequency and lightning impulse withstand, short-time and peak withstand current, temperature rise, making and breaking capacity, mechanical endurance, and degree of protection.
- Internal arc classification (IAC) verified by test, with pressure relief flaps and exhaust ducting proven to contain the arc and protect the operator. This is a distinct qualification from dielectric withstand and should be requested explicitly in tender documents.
- Third-party type-test reports from KEMA, ASTA, CESI or TUV available. Note that an ASTA certificate is signed by an ASTA observer who takes responsibility for the report, which is why utility and EPC procurement treats it differently from a manufacturer's own test record.
INCOMING MATERIAL CONTROL
- Vacuum interrupters, operating mechanisms, protection relays and instrument transformers accepted only from qualified suppliers against certificate of conformity.
- Copper busbar verified for conductivity, cross-section and plating thickness.
- Epoxy insulation components partial-discharge tested on receipt.
- Steel sheet thickness and powder-coat film thickness verified per batch; standard finish RAL 7035.
IN-PROCESS INSPECTION
- Enclosure dimensional and squareness check after fabrication.
- Busbar torque verification with calibrated wrenches, recorded against each joint.
- Wiring verified point-to-point against the approved schematic before energisation.
- Mechanical interlock sequence proven on every panel: breaker cannot be racked in with the earthing switch closed, earthing switch cannot be closed with the breaker closed, cable compartment door cannot be opened unless earthed.
ROUTINE TESTING - EVERY PANEL, NO SAMPLING
- Power-frequency withstand voltage on the main and auxiliary circuits.
- Main circuit resistance measurement, compared against the design baseline.
- Mechanical operation test through the full Service / Test / Isolated sequence.
- Protection and control function test, including trip and close from the relay.
- Degree of protection and paint film verification.
- Each panel is issued a serialised routine test report.
TRACEABILITY AND SYSTEM
- ISO 9001 quality management system.
- Serial number traceability from finished panel back to vacuum interrupter, mechanism and insulation component batch.
- Test records retained and retrievable for the warranty period and beyond, which matters when a utility raises a query years into service.
ENVIRONMENTAL QUALIFICATION
Standard IEC ratings assume a +40 C ambient. Where the destination demands more, we verify accordingly: temperature-rise testing at elevated ambient for Gulf projects, salt-spray testing for coastal installations, and GOST 15150 climatic versions with low-temperature functional verification for CIS deployment.
