When you are planning construction or an upgrade of a site, the question comes up: what equipment should you order? This guide helps the customer (a business owner, a farmer, a developer) understand which switchboards and substations you actually need.
LK Energy manufactures a full line of electrical switchboards and transformer substations for voltages of 0.4–35 kV. The material is written to answer customers’ questions and doubts directly — from choosing a switchboard to designing power supply systems.
By the incoming voltage at the site
All LK Energy equipment is designed for three voltage classes. The choice depends on the voltage that comes into your site from the grid.
0.4 kV — low voltage (private houses, shops, offices)
This is the voltage for residential sites and small businesses. Power is fed straight into the distribution cabinet.
- YaVU — incoming-metering box (for small sites: a single apartment, a country house, a shed)
- VRP — incoming-distribution device (for offices, shops and small workshops; metering + distribution + protection)
- ShchO-90 — distribution switchboard panels (0.4 kV distribution switchboard panels for currents up to 4000 A — they are assembled into the main distribution switchboard (GRSHch) of a substation or a large site)
- AVR — automatic transfer switching cabinet (if there are two incoming feeds and a backup from a generator or a second incoming cable)
- UKM — reactive power compensation units (for industrial businesses, to reduce the charge for reactive energy)
6–10 kV — medium voltage (workshops, factories, large offices, solar power plants)
This voltage is brought in when the site’s load can no longer be covered at 0.4 kV, or when the regional power utility (oblenergo) specifies it in the technical conditions. A transformer substation is then installed to step 6–10 kV down to 0.4 kV for internal distribution.
- KTP 10(6)/0.4 kV — package transformer substation (the most popular solution; a single compact unit with a transformer, 6–10 kV distribution and 0.4 kV distribution)
- STP — pole-mounted transformer substation (mounted directly on overhead line poles; needed for villages and cottage developments)
- KSO — single front-access switchgear cubicles 6–10 kV (individual compartments of medium-voltage switchgear; installed together in an RP to distribute and control the lines)
- RUNN — low-voltage switchgear (0.4 kV distribution within a substation; distributes power across groups)
- Standard KTP 10/0.4 package with RUNN (ready-made diagrams and questionnaire sheets for designers and utility services)
35 kV — high voltage (large industrial sites, solar power plants of 1+ MW)
For district-scale substations and industrial sites with a heavy load.
- KRU 35 kV — package switchgear unit (power distribution at the 35 kV level; a single package cabinet)
- KRPZ — package switchgear unit of protected design (for harsh conditions — snow, wind, dust)
- OPU — substation control buildings (the centre for control, protection and monitoring at 35 kV)
By site type
Private house
Incoming feeds — 0.4 kV. Simplicity, reliability and compactness are what matter.
- YaVU — incoming-metering box (the standard solution for residential energy metering)
- VRP — incoming-distribution device (if distribution with groups of circuit breakers is needed)
- Rooftop solar power plants for a private house (savings on electricity, backup power during blackouts)
Shop, office, administrative building
Incoming feeds 0.4 kV, often two for reliability. Metering, protection and distribution across the floors are needed.
- VRP — incoming-distribution device (two incoming feeds, distribution, short-circuit protection)
- ShchO-90 — distribution switchboards (distribution across rooms, halls and floors)
- AVR — automatic transfer switching cabinet (switching to the second incoming feed when the first one goes off)
Workshop, small factory
Incoming feeds 6–10 kV or 0.4 kV with high currents. A transformer substation, distribution and short-circuit protection are needed.
- KTP 10(6)/0.4 kV — package transformer substation (the main, most common substation for workshops)
- KSO — 6–10 kV cubicles (distribution at the incomer or multiple lines to several KTPs)
- Low-voltage switchgear up to 5000 A (for large workshops with powerful electric motors)
- RZA — relay protection and automation cabinets (protection against short circuit and overload)
- Electrical installation works (installation of switchboards, substations and cables — full cycle)
Farm, borehole, pumping station
Incoming feeds 0.4 or 6–10 kV. Automation for the pumps, dry-running protection and SCADA supervisory control are needed.
- Solar plant for an artesian borehole with SCADA control (solar energy powers the pump during the day; water is stored in a tower)
- KTP 6/0.4 kV (if the incoming feed from the district grid is at 6 kV)
- SCADA control of sewage (KNS) and water (VNS) pumping stations and boreholes (remote monitoring of the water level and of pump operation from a control centre)
- PNR — commissioning works (setting up protections and alarms before start-up)
Solar power plant (SES)
Inverter station → transformer substation → export to the grid at 10(6) or 35 kV.
- Turnkey solar power plants — to suit the situation (from 5 kW for a house to 5 MW for industry; design, installation, commissioning)
- KTP for a solar plant 10/0.4 kV (if the plant supplies loads locally or runs in parallel with the grid)
- Standard diagram KTP-1000/10/0.4 for a solar plant (ready-made RZA and AVR diagrams for a 1 MW export)
- KTP and KRP 6 kV for a solar plant — 1 MW block (high-capacity export at 6–10 kV)
- Backup power with BESS (hybrid solar plant with batteries to keep running during grid outages)
Street and car park lighting
Incoming feed 0.4 kV. Lighting control (on/off) and metering are needed.
- I-710 (UNO) street lighting control cabinets (switching on/off by schedule or by a light sensor)
- SCADA control of street lighting (remote lighting control from a smartphone, energy metering)
By engineering task
Bring in and meter the electricity supply
The choice depends on the reliability required and on the size of the site:
- YaVU — incoming-metering box (for small residential sites, apartments, country houses)
- VRP — incoming-distribution device (for offices, shops and small production facilities)
- KTP 10(6)/0.4 kV (when the incoming feed is at medium voltage; includes transformation and distribution)
- KSO — 6–10 kV cubicles (medium-voltage distribution for several lines and substations)
- Design of power supply systems (calculating the incoming capacity and the voltage your site needs)
Distribute power across the site — groups, sections, workshops
A safe distribution scheme with load grouping is needed:
- ShchO-90 — distribution switchboards (a panel-based solution; extends flexibly as required)
- RUNN — low-voltage switchgear (a package cabinet for 0.4 kV distribution within a substation)
- Standard diagram of a 0.4 kV VRP (ready-made drawings for two sizes — 400 A and 1600 A)
- Manufacture of electrical switchboard equipment (LK Energy calculates and manufactures the switchboard for the exact load of your site)
Protection against short circuits and overloads — relay automation
Systems that operate during a short circuit or a fault and safely disconnect the line:
- RZA — relay protection and automation cabinets (electronic protection devices for medium and high voltage)
- How to choose an RZA scheme for a 10 kV cubicle (a guide to protection functions: overcurrent protection (MTZ), instantaneous trip, earth-fault protection (ZZZ), AVR)
- Standard diagram of a 10 kV RP on KSO cubicles (ready documentation with relay protection for designers)
- PNR — commissioning works (setting up the protection terminals, testing, reports)
Improve the power factor — reactive power compensation
A low power factor (cos φ) leads to an extra charge for reactive energy. Capacitor units correct this:
- UKM — reactive power compensation units (calculated from measurements taken at your site)
- Standard diagram of a 0.4 kV UKM (ready-made drawings and questionnaire sheets)
- How to reduce the electricity bill for a business (a detailed article on compensation as one of the ways to save)
Backup when the main grid goes off — AVR and backup sources
Automatic switching to a backup feed, a generator or batteries:
- AVR — automatic transfer switching cabinet (switching between two grid feeds or to a diesel generator set)
- Standard diagram of a 0.4 kV AVR (ready-made diagrams for two incoming feeds + a DGU)
- Backup power for industrial sites (calculation & installation of backup systems from 5 kW to 1+ MW)
- Hybrid solar plants with batteries (backup energy from solar panels + batteries)
Step the voltage down 6(10)→0.4 kV — transformer substation
If the incoming feed is at medium voltage, a transformer substation with a step-down transformer is required:
- KTP 10(6)/0.4 kV — package transformer substation (the most popular solution)
- STP — pole-mounted transformer substation (mounted on overhead line poles for villages)
- KTPMM — sandwich panels (urban modular design, compact)
- BKTP — block-type (concrete) package transformer substation (for cities & private developments)
- Standard diagram of an STP 10/0.4 kV (ready-made diagrams and questionnaire sheets)
- Construction of substations (full cycle: from design to commissioning)
Frequently asked questions about choosing equipment
What equipment is needed to bring electricity into a private house?
To bring power into a house, a YaVU (incoming-metering box) or a VRP (incoming-distribution device) is installed — a single compact cabinet with automatic protection and a meter. A YaVU is enough for small houses; a VRP is for sites with extended distribution.
What is the difference between a KTP and a KSO?
A KTP (package transformer substation) is a separate box or container with a 6(10)/0.4 kV transformer for an entire site. A KSO (switchgear cubicle) is a single cubicle of 6–10 kV switchgear for switching lines on and off; it is installed in an RP together with other cubicles.
What is needed to connect a workshop to 10 kV from the poles?
A transformer substation is needed: a KTP 10/0.4 kV (the workshop’s equipment runs at 0.4 kV). If there are several lines, a distribution point (RP) on KSO cubicles is added on the 10 kV side. Earthing, a cable entry and lightning protection are also required.
What is needed to install a solar power plant: which switchboards?
It depends on the capacity and on where the energy is exported. A small grid-tied solar plant (roughly up to 30 kW) — an inverter and a 0.4 kV distribution switchboard (RUNN or ShchO-90), with export at 0.4 kV. A larger plant additionally needs a step-up transformer (0.4→10 kV) and relay protection for export at 10 kV. Reactive power compensation (UKM) is installed only when the power factor is low. LK Energy assembles it all into a turnkey solar plant package.
How can equipment be protected from voltage surges and lightning?
Surge arresters are installed in the switchboard near the incomer. An external lightning protection system is also required — rods on the roof and earthing. In a grid topology, a cubicle with surge arresters is added to the RP.
What should be done if the power often goes off because of grid outages?
An AVR cabinet (automatic transfer switching) is needed — it allows two incoming cables to be run from different points of the grid or from a generator. When voltage disappears on the first feed, the AVR automatically switches to the second within fractions of a second (to a generator — within a few seconds). For equipment that cannot tolerate even a short interruption (servers, medical equipment), an uninterruptible power supply (UPS) is added.
Why is a RUNN needed? Can you do without one?
A RUNN (low-voltage switchgear, 0.4 kV) is a distribution cabinet with circuit breakers that protects the lines and makes it possible to control the supply to individual workshops or adjacent areas. A RUNN is installed when there are several load groups at 0.4 kV — workshops, multi-hall offices, substations. A small office can manage with a YaVU.
Which switchboard is needed for a private house with electric heating?
A heated house needs a more powerful VRP or GRSHch (main distribution switchboard) rated from 32 A to 100 A depending on the load. It will accommodate separate circuit breakers for lighting, sockets and heating.
How do you connect a deep borehole located far from the house?
For remote boreholes, a hybrid solar plant with SCADA control is installed: the panels power the pump during the day, water is stored in a tower, and at night the backup comes from the batteries. LK Energy offers a ready-made package with remote level monitoring.
How can an industrial enterprise reduce its electricity bill?
There are several ways: (1) install reactive power compensation (UKM); (2) build your own solar plant; (3) install SCADA control to manage the load. LK Energy prepares a feasibility study and selects a solution for your situation.
What is a GRSHch and when is it installed instead of a RUNN?
A GRSHch (main distribution switchboard) is a larger and more complex version of the distribution switchboard, for large sites (buildings over 1000 m², workshops). It has backup supply (AVR) and more cells. A RUNN is a simpler switchboard for smaller sites.
Does a small business need reactive power compensation (UKM)?
A UKM is installed if the bill includes a large charge for reactive energy. For a business with motors, compressors or transformers, compensation can be economically worthwhile. A small shop or office usually does not need a UKM.
How do you choose between a pole-mounted (STP) and a concrete (BKTP) substation for a village?
An STP is mounted directly on an overhead line pole and saves space. A BKTP stands separately on the plot, is larger, but is easier to maintain. The choice depends on settlement density and local conditions.
What should you do before ordering a switchboard or a substation?
Prepare a questionnaire sheet with the parameters: voltage (0.4/6/10 kV), current, number of lines, load type (lighting, motors, heating), and whether a backup is required. LK Energy provides blank forms and examples — this is the basis for the design and for manufacturing.
What is the difference between a grid-tied and a hybrid solar plant?
A grid-tied solar plant exports all the electricity to the grid without batteries; it suits a business that operates during the day. A hybrid plant powers the site during the day and stores the surplus in batteries to run at night or during grid outages; it costs more but it provides backup.
Not sure what exactly you need?
Describe your site in plain words — we’ll suggest which equipment fits and give an indicative price. A preliminary reply usually within 24 business hours.
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