RP (distribution point) is an electrical installation for receiving and distributing electricity at a single voltage, most often 10 kV, without transforming it. RTP (distribution transformer point) is the same type of distribution point additionally fitted with 10/0.4 kV power transformers. TP (transformer substation) is an electrical installation that receives electricity at 10 kV, steps it down to 0.4 kV via a power transformer, and distributes it to consumers; its factory-built version is the KTP, a package transformer substation supplied in full factory readiness.

All three types of facility look similar from the outside — metal cabinets or a separate building housing switchgear — which is why the terms are often confused. The difference is functional: whether voltage transformation is present at the site, and which function is primary — distribution of 10 kV circuits or supplying 0.4 kV consumers.

RP — distribution without transformation

An RP receives power through one or two 10 kV incoming feeders and distributes it via outgoing lines. Structurally it is assembled from cubicles: KSO (single-front-access switchgear cubicles) for indoor installation, or outdoor-type KRUN cubicles for open-air sites. A typical two-section RP layout comprises two incoming feeders, a sectionalizing breaker with an automatic transfer switch (ATS) scheme, outgoing lines, voltage transformers (VT) with metering circuits, and station service transformers (SST).

Important: the SST (for example, TMG-25 in LK Energy's standard solutions) is not a power transformer for consumers. It supplies only the facility's own needs: control circuits, heating, lighting.

RTP — RP plus power transformers

If, within the same enclosure that houses the RP cubicles, 10/0.4 kV power transformers together with a 0.4 kV switchgear are installed, the facility is classified as an RTP. The 10 kV distribution section itself is no different from a standard RP, so the standard solutions for KSO cubicles are adapted for RTPs as well.

TP and KTP — transformation as the primary function

A 10/0.4 kV KTP consists of three units: a high-voltage switchgear (HV switchgear) with power fuses, a power transformer (in standard solutions — the TMG series), and a low-voltage switchgear (LV switchgear) — 0.4 kV cabinets with an incoming switching device, outgoing-line circuit breakers, current transformers, and a commercial metering unit.

By design, a distinction is made between pole-mounted KTPM units (on a support structure), urban-type KTPGS units (a metal enclosure with separate compartments for the 10 kV switchgear, the transformer, and the 0.4 kV switchgear), pole-type STP units, and package-type KTP units for solar power plants. In the latter, transformation works in the reverse direction: the inverters output power to the 0.4 kV side, and the transformer steps the voltage up to 6(10) kV.

Comparison table

Criterion	RP	RTP	TP / KTP
Purpose	Receiving and distributing electricity at 10 kV	Distribution at 10 kV + supplying 0.4 kV consumers	10/0.4 kV transformation and distribution at 0.4 kV
Transformation	None (only an SST for own needs)	Present — 10/0.4 kV power transformers	Present — the primary function
Standard cubicles and units	KSO or KRUN: incoming feeders, sectionalizing breaker with ATS, lines, VT, SST	RP cubicles + power transformers + 0.4 kV switchgear	HV switchgear + transformer + LV switchgear
Where used	Network nodes with a large number of 10 kV connections	The same nodes, when 0.4 kV consumers are nearby	Direct supply to 0.4 kV consumers; package-type KTP units — power evacuation from a solar power plant

How to choose

Distance to the load: 0.4 kV networks are kept short because of voltage losses, so transformation is placed as close as possible to consumers. A concentrated 0.4 kV load is a job for a TP/KTP.
Number of connections: When a single network node needs to distribute many 10 kV lines (a district, an industrial site, pumping stations), while transformation happens further along, closer to consumers — an RP is needed.
Combining both tasks: A 10 kV distribution node that also has its own nearby 0.4 kV consumers — that's a case for an RTP.
Power rating: For single consumers, the standard transformer ratings for KTP units in LK Energy's solutions are 400, 630, 1000, and 1250 kVA; the specific rating is determined by the load calculation in the project.

Frequently asked questions

There's an SST transformer in the RP — does that make it an RTP already?

No. The SST supplies only the facility's own needs (control circuits, heating, lighting). An RTP is when 10/0.4 kV power transformers are installed that supply external consumers.

How does a KTP differ from a "plain TP"?

A KTP is a package substation of full factory readiness: the HV switchgear, transformer, and LV switchgear are supplied as a finished product based on a technical questionnaire. A TP in the general sense can also be built on-site in a separate building.

What is a KRP and how does it differ from an RP?

A KRP is a switching and distribution point. Functionally it is an RP for evacuating generated power: in the standard solution for a solar power plant, it collects feeders from the plant's package-type KTP units and evacuates power to the connection point. It is built on outdoor-type KRUN-E cubicles.

RP, RTP, TP — What's the Difference and Which Solution to Choose