Live
MV-501
MV Systems & Network Explorer
3D grid-to-building network with voltage levels by utility, radial and ring topologies, and neutral earthing methods.
MV-500 · New module family
Medium Voltage Engineering Hub
Sixteen interactive labs for 6.6 kV to 33 kV networks. You can see the equipment in 3D, run the switching, calculate the ratings and test yourself, with rules for the GCC, Australia, New Zealand and Asia.
Key facts about medium voltage
- Medium voltage (MV) usually means AC systems above 1 kV and up to about 36 kV. Common values are 6.6, 11, 13.8, 22 and 33 kV.
- 11 kV is the most common building supply voltage across the UAE, Qatar, Kuwait, Bahrain, Australia, New Zealand and much of Asia.
- Saudi Arabia runs at 60 Hz with 13.8 kV and 33 kV distribution. The other GCC states run at 50 Hz.
- MV switchgear is rated one step above the system voltage: 12 kV for 11 kV, 24 kV for 22 kV and 36 kV for 33 kV (IEC 62271-1).
- Urban MV cables run as open rings, with a normally open point so a faulted section can be isolated and supply restored from the other end.
T + 0:00
Normal running
Buildings on supply
4 / 4
MV / Grid
11 kV / 132 kV
Energised
Dead
Faulted
Earthed
FPI flag
Times shown are typical for a manual switching response and will vary by utility and by how much automation the network has.
How each MV lab teaches
2D
Live single line diagrams, phasors, TCC curves and waveforms that respond as you change inputs.
3D
Rotate, explode and x-ray RMUs, transformers, cables and substations. Click any part to learn what it does.
4D
3D plus time: switching programs, fault restoration, installation sequences and project timelines you can scrub through.
Lv
Every lab has Beginner, Practitioner and Expert levels, plus a region switch for GCC, AU, NZ and Asia rules.
What MV voltages are used in each region?
These are typical utility distribution voltages. Click a row to load that region into the network simulator above. Always confirm current values with the local utility, since networks change.
| Country / utility | Typical MV distribution | Upstream | Frequency | Notes |
|---|---|---|---|---|
| UAE - Dubai DEWA | 11 kV | 132 kV | 50 Hz | Building substations fed from 132/11 kV primary substations. |
| UAE - Abu Dhabi ADDC / AADC | 11 kV and 33 kV | 132 kV | 50 Hz | 33 kV used for large loads and as subtransmission to 33/11 kV substations. |
| UAE - Sharjah SEWA | 11 kV and 33 kV | 132 kV | 50 Hz | Mixed 33 kV and 11 kV distribution. |
| Saudi Arabia SEC | 13.8 kV and 33 kV | 110 / 132 kV | 60 Hz | The only 60 Hz GCC grid. 13.8 kV is common in cities. |
| Qatar KAHRAMAA | 11 kV | 66 kV | 50 Hz | 66/11 kV primary substations feed 11 kV rings. |
| Kuwait MEW | 11 kV | 132 kV | 50 Hz | 132/11 kV primary substations. |
| Oman Nama distribution companies | 11 kV and 33 kV | 132 kV | 50 Hz | 33 kV widely used outside dense urban areas. |
| Bahrain EWA | 11 kV | 66 kV | 50 Hz | 66/11 kV primary substations. |
| Australia Ausgrid, Energex, Western Power and others | 11 kV and 22 kV | 33 / 66 / 132 kV | 50 Hz | 22 kV common in Victoria and WA. SWER lines in rural areas. |
| New Zealand Vector, Orion, Wellington Electricity and others | 11 kV and 22 kV | 33 / 110 kV | 50 Hz | 22 kV used in parts of Auckland and in rural networks. |
| India State DISCOMs | 11, 22 and 33 kV | 66 / 132 kV | 50 Hz | 11 kV is the main urban distribution voltage. |
| Malaysia TNB | 11, 22 and 33 kV | 132 kV | 50 Hz | 22 kV and 33 kV common in newer developments. |
| Singapore SP Group | 22 kV and 6.6 kV | 66 kV | 50 Hz | 22 kV is the main distribution voltage. |
| Pakistan DISCOs (K-Electric, LESCO and others) | 11 kV | 132 kV | 50 Hz | 132/11 kV grid stations. |
| Hong Kong CLP Power, HK Electric | 11 kV | 132 kV | 50 Hz | 11 kV ring networks in dense urban areas. |
Data reviewed 21 Oct 2026. Sources: utility network descriptions and published distribution codes.
All 16 MV modules
Built in four phases, plus a 4D capstone. Live modules are marked in green.
Phase 1
Foundations
Live
MV-502
MV Cables & Accessories Lab
Exploded 3D XLPE cable, sizing to IEC 60502-2, AS/NZS 1429.1 and BS 6622, sheath bonding, and 4D termination and joint install.
Live
MV-503
RMU & MV Switchgear Lab
3D ring main unit with x-ray and exploded views, a live interlock simulator, 4D switching sequences and a spec configurator.
Live
MV-504
Distribution Transformer Lab
Animated vector group phasors, oil vs cast resin, losses and MEPS, tap changers, parallel operation and sizing.
Phase 2
Design & analysis
Live
MV-505
Substation Design & Layout 3D
Room layout in 3D with live clearance checks, transformer room ventilation, oil containment and a 4D construction sequence.
Live
MV-506
Short Circuit & Load Flow Studio
IEC 60909 fault levels from the 11 kV source to the final DB, animated fault path, switchgear rating checks and voltage profile.
Live
MV-507
MV Protection & Relay Coordination
Live TCC plotting of IDMT relays, HV fuses and LV ACBs, grading margin checks, an animated trip sequence and CT knee-point sizing.
Live
MV-508
MV Earthing & Step/Touch Lab
IEEE 80 earth grid design with a 3D surface potential map and a 4D walk-through of step and touch voltages during a fault.
Phase 3
Site, T&C and operations
Live
MV-509
MV Testing & Commissioning Lab
Virtual IR/PI, VLF tan delta, TTR, winding resistance and secondary injection tests with interpretation, plus a saved ITP checklist.
Live
MV-510
Switching, Safety & Permits Simulator
Build a switching program from step cards, run it on a live ring and get scored on safety, outages and permits.
Live
MV-511
Utility Approvals & Interface Workflow
Connection stages from application to energisation, documents per stage, a critical path Gantt and a 4D project timeline.
Phase 4
Advanced
Live
MV-512
Power Quality & Reactive Compensation
Harmonic waveform lab with THD and K-factor, IEEE 519 checks, capacitor bank sizing and resonance with detuned reactors.
Live
MV-513
Renewables, BESS & EV MV Integration
A 4D day of solar, battery and EV charging on an MV connection, voltage rise at the point of connection and regional grid rules.
Live
MV-514
Digital Substation, SCADA & IEC 61850
Millisecond timeline of sampled values, GOOSE trips and SCADA reporting, PRP/HSR redundancy and process bus bandwidth.
Live
MV-515
Condition Monitoring & Failure Forensics
Duval Triangle DGA, thermography with load correction, a 12-month PD trend with PRPD patterns and failure investigations.
Capstone
4D project
Live
MV-516
4D Substation Project Simulator
Capstone: load, transformers, RMU, cable and room design with an editable BOQ, cost estimate and a 4D build programme.
Where should I start? Learning paths by level
MV Question Bank: 788 questions with answers
About 50 questions per module at three levels, with regional questions for the GCC, Saudi Arabia, Australia, New Zealand and Asia. Practise with instant explanations or sit a timed exam.
MV glossary
- RMU (ring main unit)
- Compact, factory-sealed MV switchgear with two ring cable switches and one transformer feeder. It is the building block of urban 11 kV rings.
- NOP (normally open point)
- The open switch that splits a ring into two radial feeders. Closing it back-feeds a section after a fault.
- LBS (load break switch)
- A switch rated to make and break normal load current, but not to interrupt fault current.
- VCB (vacuum circuit breaker)
- A breaker that interrupts fault current inside a vacuum bottle. It is used on transformer and feeder circuits with protection relays.
- FPI (fault passage indicator)
- A device on the RMU that flags when fault current has passed through it, so crews can find the faulted cable section.
- VPIS / VDS
- Voltage presence indicating system. The neon or LED lamps on the RMU front show whether a cable is live (IEC 62271-213, IEC 61243-5).
- LSC (loss of service continuity)
- An IEC 62271-200 class that says what stays in service when one compartment is opened. LSC2 keeps the busbar and other units live.
- IAC (internal arc classification)
- A type-tested level of protection for people if an internal arc happens, for example IAC AFL 20 kA 1 s.
- XLPE
- Cross-linked polyethylene, the standard insulation for MV power cables (IEC 60502-2, AS/NZS 1429.1).
- Ur (rated voltage)
- The highest system voltage the equipment is designed for: 12 kV gear on an 11 kV system, 24 kV on 22 kV, 36 kV on 33 kV.
- Ik / tk
- Rated short-time withstand current and its duration, for example 20 kA for 1 s or 25 kA for 3 s.
- SF6-free switchgear
- MV gear using clean air, dry air, vacuum or solid insulation instead of SF6 gas. The EU phases SF6 out of new MV gear up to 24 kV from 2026.
Frequently asked questions
What is medium voltage (MV)?
In building services and utility distribution, medium voltage usually means AC systems above 1 kV and up to about 36 kV, for example 6.6 kV, 11 kV, 13.8 kV, 22 kV and 33 kV. IEC does not formally define the term, so some utilities and standards stretch it to 52 kV.
What MV distribution voltage is used in Dubai?
DEWA distributes at 11 kV to building substations, fed from 132/11 kV primary substations, at 50 Hz. Always confirm the current DEWA regulations for each project.
What MV voltages are used in Australia and New Zealand?
11 kV is the most common distribution voltage in both countries, with 22 kV widely used in some networks and 33 kV used for subtransmission. Rural Australia also uses SWER lines. Supply is 50 Hz.
Which countries in the GCC use 60 Hz?
Saudi Arabia uses 60 Hz, with 13.8 kV and 33 kV as common distribution voltages. The UAE, Qatar, Kuwait, Oman and Bahrain use 50 Hz.
What rated voltage should MV switchgear have for an 11 kV system?
12 kV rated equipment is used on 11 kV systems. The usual IEC 62271-1 pairs are 7.2 kV for 6.6 kV, 12 kV for 11 kV, 17.5 kV for 13.8 kV, 24 kV for 22 kV and 36 kV for 33 kV.
What is a normally open point (NOP) in an MV ring?
An MV ring is built as a loop but operated radially. One switch in the loop is left open, the normally open point, so each half is fed from one source. When a cable section faults, it is isolated and the NOP is closed to restore supply from the other end. Try it in the simulator at the top of this page.