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Views: 0 Author: Site Editor Publish Time: 2026-08-20 Origin: Site
Zisheng Electric has been engaged in power distribution equipment exports for more than a decade. Over the years, we have participated in quite a number of mining power distribution projects.
These projects are located across:
East Africa
West Africa
Southern Africa
Some were for new mine construction, while others were for expansion projects of existing mines.
The biggest characteristic of mining projects is:
Equipment can arrive a few days late, but production cannot wait.
For mining companies, a power outage is not simply “no electricity.”
It means:
Mining equipment shutdown
Reduced production output
Increased labor costs
Potential impact on the entire production schedule
The urgency of mine electrification — the need to restore or establish power supply immediately — is completely different from ordinary rural electrification projects.
Mining operators calculate losses in a very direct way:
One day of downtime = how many tons of ore lost × the corresponding financial loss.
That number is usually significant.
Therefore, mining power supply projects usually focus on three key indicators:
Construction schedule
Operational reliability
Environmental adaptability
Traditionally, building a mining substation meant constructing a building, installing walls and foundations, and assembling equipment on site.
The entire process could easily take six months or longer.
During those six months, the mine’s diesel generators could consume enough fuel to cost the price of a luxury vehicle.
Later, more and more projects began adopting prefabricated substations, also known as packaged substations or containerized substations.
The concept is simple:
High-voltage switchgear, transformer, and low-voltage distribution equipment are all installed and tested in the factory in advance, integrated into a steel enclosure.
Then:
Transport it to the site
Place it on the foundation
Connect the cables
And the power supply can be put into operation.
This article will discuss what we have experienced and observed in African mining power distribution projects, as well as the actual advantages of packaged substations and how to select the right solution.
Some points come from our own project experience, while others come from discussions with mining engineers and project managers on site.
A prefabricated substation is not a new technology.
But in the specific environment of African mining projects, its value becomes much more significant.
First, let’s look at a few numbers.
Africa is one of the world’s most important sources of mineral resources. According to the African Development Bank, Africa has abundant reserves of minerals such as copper, cobalt, manganese, and platinum group metals. With the rapid development of the renewable energy industry, mine expansion and new mining projects continue to increase.
According to forecasts from the International Energy Agency (IEA), global demand for Africa’s critical minerals is expected to increase by 3-4 times by 2040.
What does this mean?
Mining operations will continue to become more numerous and larger in scale.
The demand for reliable power supply will only become more urgent.
However, mine power supply is indeed different from other applications.
When a village or town loses power, residents complain, but in most cases it does not directly threaten safety.
A power outage in a mine is a completely different situation.
If underground drainage pumps stop:
→ Water can flood the mine.
If ventilation systems stop:
→ Dangerous gases can accumulate.
If hoisting equipment stops halfway:
→ Workers may become trapped underground.
These are not exaggerations — such incidents have happened in real mining operations.
Therefore, mining sites have much higher requirements for power supply reliability than ordinary distribution networks.
If a transformer fails, a replacement must be available quickly.
Waiting three to five months for equipment shipment from overseas is simply unacceptable.
Mining loads are never truly “stable.”
When a ball mill starts, the current can instantly rise to 6-7 times the rated current.
If several large machines start at the same time, the entire distribution network voltage can drop significantly.
Under these repeated impact conditions, ordinary transformers may experience:
Loosening of windings
Insulation damage
Increased mechanical stress
Accelerated insulation aging
Mining transformers must be designed for:
High impact resistance
Strong short-circuit withstand capability
What is the environment like at a mine?
Heavy dust
Strong vibration
Limited installation space
Poor roads
Copper mine dust can also contain corrosive components.
A packaged substation installed at a mining site may sit beside heavy trucks moving back and forth all day, with constant ground vibration.
Traditional power equipment designed for cleaner environments may not survive for many years in such conditions.
One of the key advantages of packaged substations is their ruggedness:
Fully enclosed structure
No need to construct a dedicated building
Built-in enclosure protection
One major characteristic of mining projects is their temporary nature.
Examples:
Exploration projects may last only one or two years
An open-pit mining area may be exhausted within three to five years
After that, equipment needs to move to another mining area.
With traditional substations, dismantling and rebuilding can almost equal the effort of constructing a new one.
A packaged substation is different:
Load it onto a flatbed truck
Lift it with a crane
Transport it to the new location
Place it on the foundation
Connect cables
And it can be put back into operation.
Many mining sites in Africa are far away from the main grid.
Even getting an 11kV or 33kV medium-voltage line connected to the mine can already be a major challenge.
As for power quality, expectations must be realistic:
Large voltage fluctuations
Unstable frequency
High harmonic content
Transformers inside packaged substations must therefore have:
Wide-range voltage regulation capability
Harmonic resistance capability
The following table compares the differences between the two approaches:
Comparison Item | Traditional Substation (On-site Assembly) | Prefabricated Packaged Substation (Zisheng Solution) |
|---|---|---|
Construction Period | 6-12 months (civil construction + installation + commissioning) | 4-8 weeks (factory prefabrication, only cable connection required on site) |
Initial Investment | Requires land acquisition, building construction, and foundation work | No dedicated building required. Once the concrete foundation is completed, the equipment can be installed directly |
Equipment Integration | High-voltage switchgear, transformer, and low-voltage switchgear are separately purchased, creating many interfaces | Highly integrated. Delivered from the factory as a complete power supply system |
Mobility | Basically difficult to relocate. Dismantling and rebuilding is almost equivalent to new construction | Complete unit lifting and transportation. Relocation can usually be completed within one to two days |
Environmental Adaptability | Equipment is exposed outdoors or installed in simple buildings. Dust and moisture protection depend on external conditions | Fully enclosed metal enclosure. Protection level is selected according to project conditions. For outdoor mining applications, IP54 or above is commonly adopted. Higher protection levels can be provided for high-dust and high-humidity environments |
Space Requirement | Large footprint, requiring equipment rooms, operation corridors, and surrounding walls | Compact design. One enclosure typically occupies only several square meters to more than ten square meters |
On-site Workload | Extensive field wiring, commissioning, and acceptance work | All major tests completed before shipment. Minimal work required on site |
Time to Operation | Many approval and acceptance procedures, resulting in long project duration | Power can be supplied after positioning and connection, minimizing the critical project timeline |
Simply put:
A traditional substation trades time for space — build slowly, commission slowly, and create a permanent installation designed to operate for decades.
Mining projects need the opposite approach:
Use space efficiency to save time.
The equipment may be more compact and slightly more expensive, but the priority is:
The mine needs power now.
When an open-pit mine begins operation, the excavation area continuously moves deeper and expands outward.
The power supply point must move accordingly.
A packaged substation can be placed near the mining area to supply power for:
Electric shovels
Drilling machines
Drainage pumps
After several months, when the working face has advanced hundreds of meters, the packaged substation can simply be lifted and relocated together with the mining operation.
The requirements in this application are:
Frequent relocation capability
Strong vibration resistance
Convenient cable connection
Packaged substations can use plug-in cable terminals. During relocation:
Disconnect the cable terminals
Lift the unit with a crane
Transport it to the new location
The entire relocation process becomes much faster and simpler.
Power distribution in underground mines is even more challenging.
The environment typically involves:
Limited installation space
High humidity
Potential risks from gas or explosive dust
Packaged substations may need to be installed inside underground chambers where:
Ventilation conditions are poor
Heat dissipation is difficult
The special requirements for this application include:
Low-voltage side neutral point ungrounded systems
Interlocking protection between transformer and switchgear
High corrosion and moisture resistance
Specially designed cooling structures
In addition, underground mining equipment must comply with local mining safety regulations.
If mining certification is required, we strictly follow the requirements and do not force unsuitable solutions.
The load at a mineral processing plant is concentrated, but the equipment layout is usually distributed.
A common approach is:
Install a long-distance 11kV distribution line around the processing area and place multiple packaged substations along the route.
Each substation supplies power to nearby equipment.
The advantages of this distributed power supply method are:
Shorter low-voltage cable distances
Lower line losses
Fewer fault points
Tailings storage facilities are even more remote.
They are often the “nerve endings” of a mining operation.
Pumping stations need to continuously remove tailings water 24 hours a day.
A small packaged substation can solve the power supply problem locally, avoiding the need to extend several kilometers of low-voltage cables from the main plant.
Otherwise, the voltage drop and power losses on that low-voltage line alone can become a serious problem.
Mining exploration camps usually have only a few dozen people.
The electrical load is not large, but reliability is essential.
Typical loads include:
Communication equipment
Medical facilities
Kitchen refrigeration equipment
A small packaged substation (50-200kVA) combined with a diesel generator as backup can form a complete independent power supply system.
The same applies to mining living areas:
Worker accommodation
Canteens
Office buildings
The load characteristics are similar to ordinary villages and towns, but the reliability requirements are much higher.
Our mining packaged substations are not simply standard urban models shipped directly to African mining sites.
Several parts have been specifically modified based on mining operating conditions.
The enclosure of a mining packaged substation is not a simple single-layer steel box.
It uses a double-layer steel plate structure with thermal insulation material in between.
Key design features include:
Steel plate thickness starting from 1.5mm
Structural components optimized through finite element analysis
Capable of withstanding vibration and impact from heavy mining vehicles
The minimum protection rating is IP54.
For coastal mining areas or high-humidity underground environments, protection can be upgraded to IP65.
The external coating adopts a C5 heavy-duty anti-corrosion system, with the coating structure specially designed according to:
Coastal environments
High humidity conditions
High corrosion areas
The transformer installed inside the packaged substation is different from a standard distribution transformer.
Key improvements include:
Prevents winding loosening caused by:
Mechanical impact
Frequent starting and stopping operations
Provides stronger:
Short-circuit withstand capability
Mechanical strength
Provides:
Higher temperature resistance
Larger temperature rise margin
Makes insulation condition monitoring easier.
When mining grid voltage fluctuates significantly, voltage adjustment can be performed without interrupting power supply.
The internal space of a packaged substation is limited, while transformer heat generation is significant.
Therefore, heat dissipation is one of the most critical issues for mining packaged substations.
We provide several cooling solutions:
Enhanced natural ventilation + forced ventilation
Equipped with axial fans
Fans automatically start when temperature rises
Independent separation of transformer, HV, and LV compartments
Each compartment has its own dedicated cooling path.
Dust protection at air inlets
Dust filters installed at ventilation openings
Filters can be removed and cleaned regularly
Air-conditioning cooling option for extreme conditions
For extremely high-temperature environments, air-conditioning cooling can be selected.
(In mining areas with sufficient power supply, energy consumption is usually not the primary concern. Reliability is.)
Mining operators may not always have professional electrical backgrounds.
Therefore, we simplify operation procedures through several design features:
Low-voltage main switch with lock
Prevents incorrect operation.
Interlocking between HV compartment door and switchgear
The switch cannot be closed if the door is not properly closed.
Complete five-prevention interlocking system
Meets international mining safety requirements.
English operation labels
Bilingual options such as:
English + Chinese
English + French
can be provided when required.
Simplified operation manual
Instead of a thick manual that nobody reads, we provide:
Illustrated instructions
Step-by-step operation guidance
For mining equipment in Africa, one strict requirement is:
The packaged substation must fit into a 40-foot container.
This is almost an industry rule.
Typical transportation requirements:
Width: ≤2.5 meters
Height: ≤2.9 meters
If equipment exceeds standard dimensions:
Transportation costs can double
Many mining roads may become inaccessible
Weight must also be controlled within standard lifting capacity.
The packaged substation is equipped with:
Lifting lugs at the bottom
Standard crane lifting points
No special lifting equipment is required.
Item | Recommended Parameters |
|---|---|
Input Voltage | 11kV / 22kV / 33kV |
Output Voltage | 400V / 415V |
Capacity Range | 315kVA-2500kVA |
Ambient Temperature | -10℃~50℃ |
Protection Level | IP54-IP65 |
Cooling Method | ONAN / Forced air cooling |
Insulation Class | Class F / Class H |
Anti-corrosion Class | C4 / C5 |
Applicable Applications | Copper mines, cobalt mines, bauxite mines, mineral processing plants |
The customer was a medium-sized copper mine.
Originally, the power supply point was located near one mining area. Later, as the excavation face advanced nearly 2 kilometers, the low-voltage cable distance became too long.
The voltage at the end of the line dropped to only 330V (rated voltage: 400V), and large mining equipment could no longer start properly.
The mining company did not want to rebuild the overhead power lines because:
The cost was high
The construction period was too long
Production schedules could not wait
Our solution was:
A 11kV/400V, 1250kVA mining packaged substation installed on a platform next to the mining area.
The 11kV high-voltage cable was connected from the original power supply point.
The packaged substation included:
Integrated high-voltage switchgear
Transformer
Low-voltage distribution panel
The site conditions were relatively favorable.
From equipment arrival, foundation verification, cable installation, to commissioning, the entire installation period was completed within one week.
The key feature was the specially designed:
Heavy-duty I-beam steel base
The base allowed the packaged substation to be installed directly on gravel ground without a concrete foundation.
During relocation:
The base would not become stuck in soft soil
The entire unit could be lifted directly and moved
This project was even more interesting.
The customer purchased a complete power supply solution for mining electric shovels.
The packaged substations were only one part of the overall solution.
Two electric shovels operated alternately in different mining areas.
Each mining area would be excavated for several months before moving to a new location.
Each electric shovel was equipped with:
400kVA, 33kV/400V packaged substation
The units were arranged along mining roads.
The special requirement was:
Ultra-low Noise
There were villages around the mining area, and night operations could not disturb residents.
We added:
Sound insulation panels inside the enclosure
Noise-reduction ventilation louvers
Low-noise transformer cores
The operating noise was controlled at around:
55 dB
which is approximately the sound level of a normal conversation.
The customer was especially satisfied with one point:
The complete unit is rainproof and dustproof, so no additional shelter is required for outdoor installation.
Guinea’s rainy season can last for several months, and outdoor equipment is exposed to heavy rainfall.
The packaged substation is designed to withstand this environment.
The main incoming voltages used in African mining areas are:
11kV
33kV
Some large mines use:
66kV
Common low-voltage outputs include:
400V three-phase
230V single-phase
Some older mining areas still use:
415V systems
During selection, always confirm:
The incoming voltage provided by the utility company
The rated voltage requirements of major mining equipment
If the voltage does not match, all equipment becomes useless.
Mining load calculations are more complicated than ordinary projects.
The following conditions must be considered:
Maximum operating conditions
Minimum operating conditions
Maintenance operation conditions
For impact loads such as:
Ball mills
Crushers
the starting current must be included in voltage drop calculations.
The diversity factor is also critical.
Actual simultaneous operation rates in mines are often lower than what designers initially estimate, but excessive optimism can also create problems.
A recommended calculation method:
Total installed equipment capacity × diversity factor (usually 0.6-0.8) × 1.2 margin factor
When the diversity factor is uncertain, it is safer to choose a slightly higher value.
Choosing an undersized packaged substation creates bigger problems later.
Unlike replacing only a transformer, upgrading a packaged substation usually means replacing the entire unit.
The high-voltage side of mining packaged substations usually uses:
Cable incoming connection
Load switch + fuse combination unit
or:
Circuit breaker switchgear
The low-voltage side commonly adopts:
Main incoming breaker
Multiple outgoing feeders
For underground mining projects, special attention is required:
The low-voltage system must use:
Ungrounded neutral system
or:
Neutral grounding through arc suppression coil
Direct neutral grounding is not allowed.
This is not a design preference — it is a mandatory safety requirement.
The following parameters directly affect packaged substation design:
Altitude
Ambient temperature
Relative humidity
Corrosive gases
Explosion hazard classification
The same packaged substation design can perform completely differently at:
500 meters altitude
2000 meters altitude
because insulation level and cooling capability requirements change.
We once encountered a mining project where altitude was not mentioned during ordering.
After delivery, the site was found to be at:
2200 meters above sea level
The lower air density reduced cooling fan efficiency.
Additional cooling equipment had to be installed.
The result:
Additional cost
Delayed schedule
This is why environmental data must be confirmed before production.
Mining sites are remote and roads are often difficult.
When equipment fails, technical support cannot arrive immediately.
When selecting a supplier:
Do not only look at price.
Consider:
Whether they have spare parts available in Africa
Whether they have local service partners
What response commitment they can provide
A packaged substation is a complete system.
A failure may involve:
High-voltage components
Transformer section
Low-voltage section
If the supplier only manufactures transformers and not complete systems, different parties may blame each other when problems occur.
That is the situation mining operators want to avoid most.
The designed service life is:
25-30 years
The enclosure uses heavy-duty corrosion-resistant steel, and the transformer is designed according to standard operating conditions.
However, mining environments are special.
Actual service life depends greatly on maintenance quality.
Recommended actions:
Regular inspection
Cleaning
Preventive testing
Under the same configuration:
A packaged substation is usually 15%-25% more expensive than a traditional substation.
However, in mining projects, this additional cost is relatively small compared with the total construction schedule.
The savings from:
Shorter construction period
Reduced diesel generator usage
Lower site management costs
usually exceed the price difference.
Yes.
One of the biggest advantages of packaged substations is their high customization capability.
We can adjust:
Internal layout
Number of outgoing feeders
Switchgear brands
Enclosure dimensions
Colors
Even the mining company’s logo can be printed on the enclosure.
Yes.
Before shipment:
Transformer oil is filled
Oil testing is completed
The packaged substation is transported as a complete unit.
No additional oil filling is required on site.
The transformer uses:
High flash point mineral oil (flash point ≥300°C)
with safety performance suitable for mining applications.
We manufacture according to:
IEC standards
and can support customers with local certification applications.
For countries requiring mandatory certifications such as:
SANS (South Africa)
ZAM (Zambia)
we provide complete technical documentation support.
However, certification requirements vary by project and country.
Customers should confirm local requirements before placing orders.
During cooperation, we can:
Send engineers to inspect the mining site
or
Analyze customer-provided:
Site photos
Layout drawings
Equipment lists
We provide:
Layout drawings
Electrical system diagrams
Foundation drawings
Customization options include:
Voltage
Capacity
Cable entry/exit arrangement
Switchgear configuration
Color
Logo
All can be designed according to customer requirements.
After installation:
We can provide:
Engineer guidance for wiring and commissioning
Training for local electrical operators
We have spare parts resources in:
Kenya
Nigeria
South Africa
Common spare parts are available locally.
Special spare parts can be shipped from China with normal sea transportation schedules.
We have extensive experience delivering projects in Africa and can customize solutions according to:Local climate conditions、Grid conditions、Load characteristics
Our products include:oil-immersed transformers, substation transformers, pad-mounted transformers, pole-mounted transformers, dry-type transformers, and other power distribution equipment
The company owns:22 utility model patents、3 software copyrights
and has passed:ISO9001、ICE audit
If your project is located in an African mine, industrial park, or renewable energy base, and you need:Mining load calculation、Prefabricated substation design、1kV/33kV system configuration、IEC technical document preparation、EPC tender technical support
Zisheng Electric — For mining power supply, speed is essential, reliability is the real capability.
