Load flow analysis: the blueprint of your electrical installation

The energy transition is forcing organisations to look at their electrical infrastructure differently. Simply connecting new consumers or generators (such as PV panels and EV charging posts) based on simple addition is no longer enough. This poses risks to operational security.

A Load Flow analysis (also called power flow calculation) provides exact insight into how voltage, current and power move through your installation, now and in the future. It is the fundamental calculation that answers the question, "Can my installation handle this change without failing?" At HyTEPS, we do not approach this as a theoretical exercise, but as a necessary step for safe and efficient electrical design.

In brief: What you need to know about Load Flow

What is it: A simulation of the steady-state of your installation to calculate currents, voltages and losses.

When needed: In the case of expansions, integration of renewable energy, new construction or unexplained failures due to voltage dips.

The risk: Without insight, expansion leads to cable overloads, unwanted triggering of protective devices or too high/low voltages.

The solution: A detailed model in simulation software (such as Vision) that calculates scenarios before you invest.

The result: An installation designed or adapted 'First Time Right', with demonstrable compliance to standards.

For whom is Load Flow relevant?

This knowledge is essential for professionals responsible for the continuity and safety of electrical systems. We see that Load Flow analyses are crucial for:

Technical Managers & Installation Managers (IV): You must guarantee that the installation complies with NEN 1010/NEN 3140 and that new equipment does not disrupt current operations.
Engineers & Consultants: You need hard data to support a design or to select the right components (cables, transformers, protective devices).
Management & Board: You want to base investment decisions on facts. An analysis shows whether an expensive grid connection reinforcement is really necessary, or whether smart energy management will suffice.

In practice, we often see reliance on historical assumptions ("it always went well"). However, due to the increase of non-linear loads and decentralised generation, the installation behaves differently than ten years ago. Blindly relying on experience is a risk in today's complex installations.

What exactly does a Load Flow calculation entail?

At its core, a Load Flow study is a numerical analysis that determines the flow of electrical power in a connected system. It calculates the voltage at each node (bus bar), the current through each branch (cable, transformer) and the power losses in the whole.

The equation: Your installation as a water supply network

To make the operation of Load Flow tangible, you can compare your electrical installation to a water supply network. In this metaphor, voltage (Voltage) equals water pressure, while current (Ampere) is the amount of water flowing through the pipes - your cables. A Load Flow analysis then calculates whether the pressure at the end of the pipe is still high enough for the nozzle (your machine) to operate powerfully enough. At the same time, the analysis checks that the pipes themselves do not burst due to excessive pressure or excess water, which in your installation would amount to dangerous overloading or short circuits.

Deterministic vs. Stochastic

A classic 'worst-case' calculation (deterministic) adds up all maximum powers. This often leads to over-dimensioning and unnecessarily high costs. In reality, all machines are never on at 100% power at the same time.

This is why we look at statistical reality. By calculating with stochastic load flow and realistic simultaneity factors, we simulate the actual behaviour of your installation. The result is a design based not on wide safety margins and assumptions, but on data. This prevents unnecessary investments in overcapacity.

When is an analysis necessary? (Symptoms & Triggers)

You do not always realise immediately that there is a problem with load distribution until it goes wrong. A Load Flow study is necessary in the following situations:

1. Operational problems (Symptoms)

Voltage complaints: Lighting flickers or sensitive electronics fail when large motors switch on. This indicates excessive voltage drops across cabling.
Overheating: Cables or distributors get hot, even if the measured current seems to be within the nominal values (often a combination with harmonics, but load flow is the basis).
Wrongly addressing protection: Circuit breakers tripping without an obvious short circuit, often due to underestimation of starting currents or selectivity problems.

2. Plant changes (Triggers)

Integrating PV and Wind: Feed-in provides voltage boosts. Without calculation, voltage can rise so high that inverters fail or equipment is damaged.
Installation of EV chargers: Charging posts require high power for long periods of time. Is there still room on the transformer?
New construction or renovation: Is the chosen cable cross-section sufficient over the length of 200 metres to keep the voltage drop within 5% (according to NEN 1010)?

Proactive analysis prevents you from having to replace cables afterwards or shutting down production.

From data to insight: The analysis process

Reliable Load Flow analysis at HyTEPS follows a structured process. Garbage in = Garbage out; therefore, we pay a lot of attention to modelling (see also our view on Modelling).

Data Collection & Validation: We inventory Single Line Diagrams, cable lengths, cross-sections, transformer data and load profiles. Missing data is verified in the field.
Modelling (Digital Twin): We digitally recreate your installation in simulation software (such as Vision or ETAP). In this, all impedances and components are accurately recorded.
Scenario determination: together, we determine the scenarios. For example: Normal Operation, Emergency Operation (emergency power), and Future Expansion (+20% load).
Simulation & Analysis: The software calculates nodal voltages, branch currents and power factors. Our engineers analyse the results: where do bottlenecks arise? Where do we exceed the standard?
Reporting & Advice: You do not receive a pile of figures, but a clear report with conclusions. We advise concrete measures, such as weighting a cable, moving a transformer stage (tap-changer) or redistributing groups.

Case study: expansion of production line in food industry

A customer in the food industry wanted to add a new production line. The house installer indicated that the main distributor was "full" and recommended a new transformer (cost: €80,000+).

The HyTEPS approach: We performed a Load Flow analysis including a measurement of the actual load (which is often lower than the nameplate states).

Analysis: The simulation showed that the transformer did have capacity, provided the reactive current (kVAR) was compensated. It also showed that the simultaneity of the motors was lower than assumed.
Solution: Installation of a capacitor bank for Power Factor correction.
Result: The new line could be safely connected to the existing transformer. The investment in the capacitor bank was a fraction of the cost of a new transformer. Operational reliability ensured, costs saved.

Common mistakes in capacity calculations

Blinded by nameplates: Adding up the powers on nameplates (rated power) gives unrealistically high consumption. Motors rarely run at full load. This leads to expensive over-dimensioning.
Neglecting Cable Lengths: With long cables, the voltage drop (Voltage Drop) is often the limiting factor, not the maximum current (Ampacity). A cable can handle the current, but if the voltage drops 10% at the end, the machine will not work.
Impedances not entered correctly: As described in studies on modelling, the exact resistance and reactance of cables is crucial. An assumption in this can lead to large deviations in the calculated short-circuit currents and voltage levels.
Failure to take asymmetry into account: In low-voltage networks, loads are often unevenly distributed over the three phases. A symmetrical calculation misses the overloading of the neutral conductor.

How do you optimise your power flows?

Do you have doubts about the capacity of your installation or are you facing an expansion? Waiting for the automaton to trip is not a strategy.

What you can do yourself:

Make sure your single-line diagrams (Single Line Diagrams) are up to date.
Inventory the capacities of planned new equipment.
Make sure you have recent measurement data of your current load profile.

When to engage HyTEPS? If the installation is complex, the stakes are high (downtime is not an option), or if you are dealing with Power Quality issues. Our engineers combine measurements with simulations to provide conclusive advice. We look beyond the standard norms and make sure your installation is robust for the future.

More on electrical analysis

Deepen your knowledge with related topics from our knowledge base:

Short-circuit calculations: What happens when things go wrong? Are your protections selective?

Harmonic analysis: The impact of pollution on your capacity.

Power Factor (Cos Phi): improving efficiency and reducing reactive current.

Voltage dips: Causes and solutions for short-term outages.

Do you want certainty about the capacity of your installation?

Don't be surprised by unforeseen outages or unnecessary costs. Speak to an engineer from HyTEPS about your specific situation. We will be happy to help you with a clear diagnosis or a complete Load Flow study.

Call: 0492 37 12 12

Mail: office@hyteps.nl

HyTEPS

Beemdstraat 3

5653 MA Eindhoven