PVAPillar 03 · System Security

Probabilistic Voltage Assessment.

How much can the point absorb before voltage collapses?

PV/QV-based voltage-stability margin, effective short-circuit ratio and reactive-support siting — evaluated automatically across every candidate point of interconnection in the scenario library.

PV / QV curvesVoltage-stability marginEffective SCR / MIFReactive-support siting

Why it matters now High inverter penetration on weaker parts of the network is driving voltage instability — one of the quiet reasons connections get delayed or curtailed. Voltage has to hold across the full range of operating conditions, and the reactive support has to be sized for it. PVA confirms both, and sizes the plant that delivers it.

Industry context, 2025 — IEA, Ember, market forecasts and a 2025 survey of 100+ energy professionals.

PV/QVMargin scoring

SCR/MIFGrid strength

Per POIAutomated sweep

MVArSupport siting

The signature output

The nose curve tells you how much headroom is left.

Voltage against transfer at a candidate point — for a strong grid and a weak one. The nose is the collapse point; the distance to it is the stability margin.

PV nose curve · voltage stability margin · candidate POI

A weak grid collapses far earlier. PVA prices the reactive support — and sites it — needed to push the nose out to the required transfer.

The full picture

Every node, every hour — violations found, reactive support sized.

A configuration-driven engine that orchestrates DIgSILENT PowerFactory across the full 8 760-hour dispatch — flags every node breaching 0.90 / 1.10 p.u. at 400, 275 and 132 kV, then sizes the reactive support portfolio that clears them. Illustrative data.

Violation heat map · 8 760 h · GB transmission · per-node hours outside 0.90 – 1.10 p.u.N-0 baseline · MC-200 · illustrative

	Node	kV	Zone	Type		MVAr
01	Location A	400	Z1	HIGH-V	1,240	250
02	Location B	275	Z1	HIGH-V	1,180	220
03	Location C	400	Z14	LOW-V	980	200
04	Location D	275	Z1	HIGH-V	980	180
05	Location E	400	Z14	LOW-V	860	180
06	Location F	275	Z2	HIGH-V	720	150
07	Location G	400	Z14	LOW-V	720	140
08	Location H	400	Z3	MIXED	680	130
09	Location I	400	Z1	HIGH-V	540	100
10	Location J	400	Z6	LOW-V	520	100
11	Location K	400	Z6	LOW-V	510	110
12	Location L	400	Z6	LOW-V	480	90
13	Location M	400	Z2	MIXED	440	80
14	Location N	275	Z14	LOW-V	420	70
15	Location O	400	Z2	MIXED	420	75

Inside the engine

Voltage security, POI by POI.

PV / QV curves

Swept automatically at every candidate POI to find the voltage-collapse point.

Margin scoring

Distance to the nose scored as the voltage-stability margin under each scenario.

Effective SCR

Short-circuit ratio and mode-interaction factor quantify grid strength at the connection.

Reactive siting

Recommends where and how much dynamic or static reactive support is required.

The read

A weak connection collapses far earlier — PVA quantifies the margin and sites the reactive support needed to reach the required transfer.

Next step

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consulting@velonenergy.com