Suspension
Carries the conductors on a stretch with little change of direction. Typically hanging insulator strings.
Guide contents ↓
POLAND · GRIDS AND INDUSTRIAL CONNECTIONSFIELD GUIDE / 01
Understand the system. Check the site. Ask the right questions.
From a line on the map to 20 MW on your site.
A visual guide to the energy backbone of factories, data centres and large investments. See where power flows, what limits capacity, and what actually confirms that a connection is possible.
12 modules5 interactive exercises1 exportable briefSources checked: 26.09.2026
Guiding principle
A site has energy value when there is a feasible path to deliver power, reliability and timing.
01 · Proximity
What is nearby?
02 · Access
Where can you connect?
03 · Capacity
How much can you actually draw?
04 · Timing
When will the infrastructure be ready?
Read in order or jump to the tools. All numerical scenarios and drawings are educational examples. The guide supports screening and conversations with the designer and the operator; it is not an electrical design.
01 / Mental mapThe same energy.
UNDERSTAND THE BASICSThe same energy.
Different voltage levels.
A higher voltage carries the same power with a lower current. Successive substations step the voltage down and distribute the energy. Not every customer passes through every level. [1]
400/220
kV · EHV
kV · EHV
Transmission grid — the system’s “backbone”
PSE. Connects the nodes of the national system. For a plant it matters as the source feeding the regional network or, in specific projects, as the level of direct connection.
group I: >110 kV
110
kV · HV
kV · HV
Regional high-voltage network
Usually a DSO network. An important option for large plants: a 110 kV connection and the plant’s own 110/MV substation.
group II: 110 kV
15/20
kV · MV
kV · MV
Local medium-voltage distribution
Often 15 or 20 kV; 6, 10 and 30 kV also occur. From the GPZ to the local network and customer substations. It can supply industry if the local configuration allows.
group III:
>1 and <110 kV
>1 and <110 kV
0.4
kV · LV
kV · LV
The last stage — installations and equipment
400 V between phases, 230 V between phase and neutral. A large plant has many local circuits; some machines may run directly on MV.
IV / V:
depending on parameters
depending on parameters
Connection groups are assigned to the connection, not inferred from how a tower looks. Group VI covers certain temporary connections. [2] Note on Polish abbreviations: NN = extra-high voltage, nN = low voltage.
A GPZ does not “produce” capacity.A GPZ (main supply point) is most often a 110/MV substation, e.g. 110/15 kV. It transforms the voltage and routes energy into the MV network. What it can deliver also depends on the network that feeds it.
There is no single threshold of “from X MW always 110 kV”.The connection level follows from network conditions, the load profile and the operator’s analysis. Ranges in a particular DSO’s forms are not a universal rule for Poland.
What do you see in the field?
Recognising the structure helps you read how the network runs. It does not prove the voltage, ownership or spare capacity. Below are illustrations of typical functions — not to scale and without the features of any specific tower series.
Tension / strain
Takes the conductor tension and separates tension sections. The insulators usually run along the conductor.
Angle
Used where the route changes direction. Often also a strain structure.
Terminal
Ends an overhead section, e.g. at a substation. Must take the conductor forces from one side.
Cable
Transition from overhead line to cable: terminations and cable descent. It is not a transformer.
Special
Adapted to particular crossings: rivers, valleys or forest. Dimensions follow from the design.
A line circuit ≠ a single conductor.A three-phase circuit has three phases. One phase can be a bundle of several conductors. Earth wires may run above them, including OPGW with optical fibre. Two circuits on one tower still share the structure and its failure risk.
Overhead
Conductors on towers. Common in 110/220/400 kV networks and also at MV. The route is visible but needs space, agreements and operational access.
On the site: corridor and conflicts
Underground cable
Conductors below ground, in ducts or tunnels. Common at LV and MV; also used at 110 kV. Takes less space above ground but still needs a corridor, land rights and access for repairs.
On the site: route and underground infrastructure
How to identify a line safely during screening?
- Read the markings on available maps and operator materials; record the date and source.
- Link the line to substation names and circuit routes. Treat the tower shape alone as a hint.
- Verify the voltage, the owner and the status: existing, under construction or planned.
- Check planning documents and site constraints. Do not apply one corridor width to every line.
Observe only from publicly accessible places. Identification never requires approaching equipment or entering a substation.
The role of suspension and strain towers, substations and route planning: PSE — Q&A [3]. Drawings: our own educational schematics.
A line carries.
A substation connects and transforms.
The connection point is the designated place where your installation joins the network. It can be many kilometres from the nearest line. Its location and requirements are set by the operator.
A / Link
Line
Carries energy between facilities. It has a defined current rating, parameters and operating arrangement.
B / Node
Substation
Distributes energy, switches circuits and protects the network; with transformers, it also changes the voltage.
C / Agreed place
Connection point
A specific place resulting from the analysis and the connection conditions. It is not chosen by distance alone.
Anatomy of a 110/15 kV substation
Read from the left: input → distribution → transformation → outputs. A functional drawing, not a construction diagram. On a small screen, scroll the diagram sideways.
A bay is the set of equipment serving e.g. one line or one transformer. A “free bay” does not automatically mean free capacity.
Busbars are the common electrical node of the switchgear. How they are split and protected affects the consequences of a fault.
Transformer steps the voltage down. Its MVA rating is only one of the limits of the whole system.
Four points worth distinguishing in documents.The connection point, the point of supply, the ownership boundary and the metering point need not be the same place. The conditions and the agreement should identify each of them unambiguously, along with the scope of responsibility.
20 MW is power.
175.2 GWh is energy.
Power describes the rate of consumption at a given moment. Energy is consumption accumulated over time. MVA describes apparent power, which matters for loading transformers and conductors.
Set the load profile
Model: a year of 8,760 h, balanced three-phase system, sinusoidal waveforms, no losses. The average/peak ratio is the load factor — not simply the number of operating hours.
Average demand
20 MW
Annual energy
175.2 GWh
Peak apparent power
21.05 MVA
E = Pavg × 8,760 h
S = P / cos φ
I = P / (√3 × U × cos φ)
S = P / cos φ
I = P / (√3 × U × cos φ)
Same demand, different current
Common linear scale, phase current. This is a physical comparison — not an assessment of a line’s permissible loading.
For 20 MW: approx. 810 A at 15 kV and 110 A at 110 kV.A higher voltage lowers the current. For the same resistance, heat losses grow with the square of the current (I²R). That is why large capacities and long distances change what the infrastructure must do.
Connection capacity
The parameter the connection is designed for, set in the connection documents.
Contracted capacity
The parameter set in the supply and billing agreement. It is not automatically equal to current consumption.
Critical load
The part of the load you must keep during a fault. For a 20 MW plant it might be, e.g., 8 MW — that is a process decision.
Try it / 01
Set 20 MW and an average demand of 60%. Does annual energy fall to 105.12 GWh? Does the peak current fall too?
Show the explanation
Energy falls to 105.12 GWh, because on average you draw 12 MW. The peak current does not change: peak demand is still 20 MW. Lower annual consumption does not remove the need to deliver full power at peak.
Two cables.
But two independent supplies?
N−1 asks whether, after losing one element, the required load can still be served. The number of cables or transformers alone is not enough. What matters is their capacity, shared elements and how they switch over.
20 / 20 MW
In this state the model covers the demand.
The remaining elements have sufficient capability in the model.
Normal state. Two transformers add capability but do not prove resilience to every fault. This tests the selected event; it is not a certificate that the whole system complies with N−1.
Simulator assumptionsEach transformer: 25 MVA, cos φ = 0.95, i.e. 23.75 MW. In the example both circuits and sources have sufficient rating; existing customers draw 0 MW. We show the state after switchover, without load-flow calculations. On a small screen, scroll the diagram sideways.
N−1 does not mean “zero milliseconds of interruption”.You also need protection, automation and a defined restoration time. A UPS, storage or a generator solve other parts of the continuity problem. A dual source can still feed a single shared customer switchgear.
Try it / 02
Choose “Two paths, shared source” and a source fault. Then separate the sources. Finally set 30 MW and switch off transformer T1.
What should you notice?
A shared source can take out both paths. Separating the sources removes that particular common point. After losing one transformer, 23.75 MW remains: enough for 20 MW, but 30 MW falls 6.25 MW short. The “customer’s shared busbar fault” test shows a risk that separating the sources does not remove.
Why doesn’t 2 × 25 MVA mean “50 MW available”?
Step 1
MVA → MW
At cos φ 0.95, 50 MVA corresponds to 47.5 MW in this simplification.
Step 2
N−1 test
After losing one transformer, 23.75 MW of transformation capability remains.
Step 3
Other loads
If other customers need 12 MW, 11.75 MW remains arithmetically.
Step 4
The whole network
Lines, voltages, short-circuit levels and other commitments may restrict this further.
11.75 MW is the result of an illustrative model, not a confirmation of connection capacity.
Three architectures.
Different scope of investment.
The arrangements below show the idea. In practice the operator sets the connection point, the requirements and the scope of work; ownership of each element follows from the agreement. On a small screen you can scroll the diagram sideways.
What gets built?
An HV connection, a 110/MV substation, MV distribution and local MV/LV substations. The ownership boundary and the split between investor and DSO are set by the agreement.
What must you check?
Point of connection and bays, line arrangement, transformation reserve, route rights, automation, metering and operating costs.
- A / MV: GPZ 110/MV → MV connection → customer MV/LV substation. Check the feeder rating and the GPZ.
- B / 110 kV: 110 kV network → customer 110/MV substation → internal MV network and local substations.
- C / PSE node: 400/110 kV substation → new 110 kV circuit → customer substation. May require network reinforcement above the connection point.
A 110 kV connection “from a PSE substation” can still be a connection to the DSO.The presence of a 400/110 kV node does not decide who your agreement is with. A direct connection above 110 kV is a separate group I option, requiring the appropriate analysis and infrastructure.
Looping into a line
May require rebuilding the line arrangement, e.g. bringing it into a substation. It is not an arbitrary “tap from the nearest tower”.
Connecting at a substation
May require a bay, space for switchgear, equipment and a new route to the customer. Free land next to the substation is not enough.
Network reinforcement
The constraint may lie further away: on the 110 kV line, the 400/110 kV transformation or another supply element.
The nearest line
does not have to mean the best site.
Brief: the plant draws up to 20 MW, target start Q1 2030, and must keep 20 MW after a specified single-element fault. Compare three locations. All names, distances and dates are illustrative.
Situational diagram, not to scale and without geographic reference; on a small screen scroll it sideways. Solid line = existing infrastructure; dashed = hypothetical route or planned investment.
A / Proximity is excellent. Access remains unknown.
A 110 kV line runs 100 m from the site. We do not know the designated point, the capacity reserve or the date. A line at the boundary may restrict building, and the connection may require a much longer route.
Next step: confirm the operator, the substations at each end of the line and the technical feasibility of connecting.
Infrastructure and accessGood proximity
Capacity certaintyUnconfirmed
Timing certaintyUnconfirmed
Evidence stageL1 · Infrastructure
| Parameter | Site A | Site B | Site C |
|---|---|---|---|
| Nearest 110 kV | 0.1 km | 1.4 km | 4.0 km |
| Actual path | Unconfirmed | 3.2 km from the substation in the WP | Depends on the new substation |
| Document | Map | WP: 20 MW; no signed agreement | Development plan |
| Timing | None | 2030 in the draft agreement, with dependencies | 2032 in the plan; misses the 2030 target |
| Conclusion | Check the point and capacity | Proceed to reviewing the conditions and agreement | Do not base a 2030 start on this investment |
Try it / 03
Which location do you take forward for further analysis? Can you already write “20 MW guaranteed in 2030”?
Show the reasoning
B has the strongest starting point, because a technical path and capacity have been identified. You still need to check the scope of the WP, its validity, the conditions for keeping 20 MW during a fault, the agreement, the schedule and the dependencies. A may turn out better after analysis; for now the evidence is missing. C does not support the assumed date.
Tutorial: in what order should you assess a location?
- Start from demand, not from the mapRecord peak and average demand, the daily profile, ramp-up stages and critical load. For a data centre, separate IT load from total facility demand.
- Establish the operator and the existing networkIdentify the lines, GPZs, 220/110 or 400/110 kV substations and how they connect. Separate existing elements from planned ones.
- Check the path to the connection pointEstimate the real route, not the straight-line distance. Count the crossings of roads, railways, rivers, buildings and land held by other owners.
- Get the operator’s answerAsk about the point, voltage, capacity in normal and outage operation, scope of work and dates. Record the date, source and conditions of the answer.
- Make a recommendation with three ratingsRate infrastructure, capacity certainty and timing certainty separately. Do not turn missing data into zero MW or into “medium certainty”.
Signs worth checking further
- A substation and a realistic corridor to the site.
- Confirmed potential for reinforcement.
- Two paths with their shared elements identified.
- Conditions covering the required capacity and scope of work.
These are grounds for analysis, not proof of power delivery.
Risk signals
- “100 MW available” without an operator document.
- WP validity unknown or the document has expired.
- Many land rights still to secure.
- Start dependent on an unconfirmed investment.
- Independence based only on the number of cables.
“20 MW available”
needs evidence.
This ladder is a project tool, not an official classification. Choose a level and see what conclusion it supports and what it does not yet confirm.
L1
Infrastructure
A specific line or substation has been identified nearby.
Neither available capacity nor a connection point has been confirmed.
Next evidence: Topology: how lines, substations and operators connect.
Always attach the evidence metadata.Source and author · document date · facility and connection point · MW · operating mode · required investments · timing and dependencies · validity · version. An old document may not justify today’s assessment.
Map
Confirms that a facility exists or is planned, within the scope and currency of the map. It does not reserve capacity.
Connection conditions (WP)
Describe the technical path and requirements. Read the whole document, including conditions, dates and validity.
Connection agreement
Sets out the parties’ obligations. Check the schedule, dependencies, scope of work, payments and the consequences of delays.
Two streams of work.
One commissioning date.
The operator’s infrastructure and the customer’s installation must be ready at the same time. The date the conditions are issued is not the connection date. The design process has no single universal length.
01
Brief and screening
Capacity, profile, date, reliability, location and alternative sites.
Output: scope of needs02
Application and required payments
The DSO’s current form, technical annexes, land documents, the application fee and the advance payment — according to the procedure.
Output: complete application03
Operator analysis and WP
Assessment of the load’s impact on the network, the point and voltage, and the work needed on both sides. Refusal or a different option is possible.
Output: technical response04
Agreement and security
Scope, responsibility, dates, settlements and dependencies. Confirmation of the required security.
Output: obligations of the parties05
Design, land and permits
Route, property rights, decisions, consents, substation and equipment design. Some activities can run in parallel.
Risk: route and formalities06
Procurement and construction
Lines, bays, transformers, the customer substation, internal installation. Dependencies on network reinforcement and equipment availability.
Risk: delivery lead times07
Testing and readiness on both sides
Protection, metering, control, agreed tests and required acceptances. Verification of operational readiness.
Output: ready for energisation08
Supply agreements and energisation
A distribution/transmission agreement and a sales agreement, or an appropriate combined agreement, settlements, and the energisation procedure.
Output: facility energisedProcess skeleton and document examples based on TAURON’s connection procedure for production and service facilities [4]; extended with the project dependencies of a large investment.
The milestone to watch
1 year
Validity of standard WP from 30.04.2026
According to current TAURON information, conditions issued from that date are in principle valid for one year from delivery. Signing the agreement within that time extends validity for the term of the agreement. There are exceptions; older cases require checking the transitional provisions. [5]
Prepare specifics for the application
- Location, the required land declarations and a site plan. [8]
- Peak and average demand, profile, growth stages.
- Single-line diagram and equipment parameters.
- Start-ups, harmonics, reactive power and other disturbances.
- PV, BESS, generators: parameters and operating mode.
- Critical load, acceptable interruption, target date.
What about storage, PV, a generator or a PPA?
PV can reduce annual consumption from the grid, but without the right configuration it does not provide supply after a grid outage. BESS has separate power (MW) and capacity (MWh): 20 MWh of storage for a 20 MW load gives, in theory, one hour before reserves and losses. Generators must be matched to the load and their operating mode agreed. A PPA is a commercial arrangement and does not by itself increase connection capacity.
The connection fee
is only part of the total cost.
Two 20 MW projects can need a completely different scope of work. What counts: substations, the length and difficulty of the route, network reinforcement, land rights and the ownership split.
01 / Operator
Connection fee
For standard MV/HV customers, TAURON’s 2026 tariff sets the rule of ¼ of the actual connection expenditure. Check exceptions and special regimes in the tariff and the agreement. [6]
02 / Investor
Own infrastructure
Customer substation, switchgear, internal installation, protection and continuity systems. Their budget is not calculated by automatically applying 25%.
03 / Delivery
Preparation and risk
Designs, land rights, consents, financing, a contingency for changes. The cost of delayed production may matter more than the length of the cable.
25% does not mean 25% of the whole project or of every network reinforcement.Arithmetic example: if the agreed base is PLN 8 million, ¼ is PLN 2 million. If your own installation costs another PLN 6 million, that makes PLN 8 million before other items and taxes. This illustrates the calculation; it is not a quote or a per-MW tariff.
Additional financial requirements — 20 MW example
New application from a standard MV/HV customer, one 20,000 kW connection; current TAURON information. The amounts do not cover the whole investment budget. [7]
| Item | Rule | For 20 MW | Meaning |
|---|---|---|---|
| Application fee | PLN 1/kW, max. PLN 100k | PLN 20,000 | Before submitting the application. |
| Advance payment | PLN 60/kW, max. PLN 6 million | PLN 1,200,000 gross | Credited towards the connection fee; under the procedure, within 14 days of the application. |
| Agreement security | For this example: PLN 30/kW | PLN 600,000 | Under the procedure, within 14 days of signing the agreement; various forms available. |
Do not add the advance payment a second time to the full connection fee. The security need not be a final cost: its form and release affect capital requirements. Cases started before 30.04.2026 follow transitional rules — check the operator’s current notice. [8]
Four things that push the start date back
- No route rights or decisions.
- Delivery of transformers and equipment.
- Dependence on earlier network reinforcement.
- Operator and plant readiness out of sync.
What to ask about the date?
“Does the date refer to building the connection, energising it, or the availability of the full 20 MW? Which investments are preconditions? Which milestones are commitments and which are assumptions?”
Do not assume a standard number of years without a delivery path specific to this location.
Build a site brief.
Fill in a few fields, tick the evidence you hold and download a note for further analysis. Brief completeness measures how well the information is prepared; it does not assess available capacity.
Your next step
CHECKLIST COMPLETENESS
Identify the site, the needs and the operator.
Do not declare MW, voltage or a date.
CHECKLIST COMPLETENESS
0 / 12
Tick only documented items. A high checklist score does not replace conditions or an agreement.
Data is stored only in this browser. Nothing is sent. Download the brief to keep a copy.
Five questions for the operator on a 20 MW project
- Which point and voltage can serve the described load profile?
- What capacity will be available in normal operation and after an agreed single-element fault?
- What work is needed on the side of the operator, the upstream network and the customer?
- What dates and dependencies apply to the stages and to full capacity?
- Which documents, payments and validity periods apply to our application?
A small glossary.
A big difference in the conversation.
DSO / TSO (OSD / OSP)
Distribution / transmission system operator (DSO / TSO). The DSO runs the distribution network; in Poland the TSO is PSE.
GPZ / SE
GPZ: main supply point, usually a 110/MV substation. SE: electrical substation — a broader term covering substations with various functions.
WP
Connection conditions (warunki przyłączenia). They set the technical requirements and the scope needed to connect a given facility.
PPE
Point of energy consumption — the identifier of the point used for metering and billing. Do not automatically equate it with the ownership boundary.
MW / MWh / GWh
MW is active power. MWh and GWh are energy. 1 GWh = 1,000 MWh; 1 MW drawn for one hour gives 1 MWh.
MVA / cos φ
MVA is apparent power. In a sinusoidal model P = S × cos φ. For distorting loads, distinguish cos φ from the total power factor.
Circuit / bay / busbars
Circuit: the three-phase circuit of a line. Bay: the equipment serving a given element. Busbars: the common node of the switchgear.
N−1 / common-cause failure
N−1 examines the effects of losing one element within a defined scope. The failure of a shared structure, switchgear or route can take out several seemingly separate paths.
Upstream / upstream network reinforcement
System elements on the supply side of your point, e.g. the 110 kV line and the 400/110 kV transformation. Their limits can block a project.
Energisation / full readiness
Energisation means applying voltage. It does not always mean you can immediately draw the full target capacity, that process testing is complete, or that all reserves are in place.
Current rating / available capacity
The current rating is the permissible loading of an element under defined conditions. The capacity available to a new customer follows from an analysis of the whole system and its commitments.
Easement / technology corridor
An easement governs the utility’s use of a property. The technology corridor relates to operation and the restrictions around a line; its extent is set for each specific investment.
Sources and currency
Based on the material provided; layout, diagrams, calculations and scenarios prepared for learning. The official sources below were checked on 26.09.2026. Financial and procedural rules are shown mainly using TAURON as the example; for a specific project, use the documents of the relevant operator. Sources are in Polish.
- [1] PSE — system description ↗
The role of transmission and distribution voltages and transformation.
- [2] Grid code regulation — consolidated text ↗
Journal of Laws 2025 item 919, regulation of 22.03.2023; connection groups and system operating conditions. Also check the amendments listed on the act’s page.
- [3] PSE — technical and formal questions ↗
Substations, towers, routes, easements and the investment process.
- [4] TAURON — production and service facility ↗
Process stages and documents for MV and HV connections.
- [5] TAURON — questions and answers ↗
WP validity from 30.04.2026, exceptions and the link to the agreement.
- [6] TAURON — 2026 tariff, chapter 4 ↗
Connection fees; point 4.3 — standard group II/III customers, with exceptions.
- [7] TAURON — payments at connection ↗
Application fee, advance payment and security for obligations.
- [8] TAURON — notice of 25.09.2026 ↗
Process changes and transitional provisions after the amendment of the Energy Law.
- [9] PSE — extra-high-voltage network plan ↗
A starting point for identifying infrastructure. The map does not confirm capacity for a site.
- [10] TAURON — forms and model agreements ↗
Current documents to check when preparing an application.
The grid operator and the energy supplier are different roles.PSE is responsible for the transmission grid. The main DSOs include PGE Dystrybucja, TAURON Dystrybucja, Enea Operator, Energa-Operator and Stoen Operator; local DSOs also operate. Establish the right operator for the specific location and network, not just by region or the name on an invoice.
ftCEE / INDUSTRIAL GRID GUIDE / POLAND
Guiding example: site screening for 20 MW · FirmMW contextVersion 1.0 · 26.09.2026
Knowledge → evidence → decision
Guiding example: site screening for 20 MW · FirmMW contextVersion 1.0 · 26.09.2026
Knowledge → evidence → decision