Voltage stability · continuation power flow
Load / DG scaling factor λ is increased in adaptive steps and the existing load-flow solver is solved for real at every point: the P–V curve, the nose (critical) point, the Q–V curve and the per-bus voltage-stability margin and risk level come from the engine.
This page needs a scheme before it can calculate
Every study here (load flow, short circuit, harmonics, cables…) runs the real engine on real engineering data, so a scheme must exist first. There is none yet — so instead of an empty page, here is how to start.
GRID-10kV → 1250 kVA transformer → LV bus → 600 kW load + 300 kvar PFC. Loaded in one click; replace the data with yours at any time.
Load the example and continue →In the studio: place devices, wire them, pick models — that becomes your project scheme (exportable drawings / BOM / report).
Open the studio →Use the chat bubble bottom-right, or Contact us — we will set the example to your site parameters.
Note: every number comes from the engine. With no scheme, nothing is invented.
Definitions, units and why the number matters for selection and quotation. Searchable, grouped by topic, collapsed by default.
Every ? mark on this page opens the same explanation in place — no page change.
7 term(s) shown of 7
Per-unit bus voltage in a load-flow result: the node voltage divided by its base voltage, so 1.00 pu is nominal.
Why it matters: It is the acceptance number of every voltage-drop check (commonly 0.95–1.05 pu). A node below the band means equipment malfunction and a grid-code breach, and the answer is a larger cable, a different transformer tap or a compensation device — a quotation change, not a note.
Point of common coupling (PCC): the interface in the network where the customer installation and the utility network are coupled, and therefore where the connection conditions apply.
Why it matters: It defines what the utility may complain about and what you must prove: voltage band, harmonic distortion, flicker and voltage-dip behaviour are all specified at the PCC, not at the equipment terminals. Studies or measurements made somewhere else do not demonstrate compliance.
Reactive compensation rating Qc: the output of the capacitor bank, sized as Qc = P × (tan φ1 − tan φ2) to move the installation from its present to its target power factor.
Why it matters: It is the item being quoted, and its usable output drops in a harmonic-rich network unless a detuned (reactor-protected) bank is used. The target power factor is a customer input, not a default — quoting a bank without stating the target pf is not a complete offer.
Maximum loadability factor λmax of the continuation power flow: the multiplier applied to all loads at the nose point of the PV curve, the point where the voltage collapses.
Why it matters: It is the loading margin of the design: λmax = 1.35 means the network only collapses at 135 % of today load. Planners require a minimum margin (the number differs between grid codes — state the criterion used), and it decides whether a line reinforcement or more reactive compensation has to be quoted.
Low-voltage ride-through: the duty (and the capability) of a generator or inverter to remain connected while the voltage at the PCC dips along a specified voltage-versus-time profile, instead of tripping off.
Why it matters: It is a grid-connection condition in most markets: a plant that cannot ride through the required curve cannot be connected or must be retrofitted. Confirm the required LVRT curve before sizing the inverters, because it decides the hardware class.
Per-unit value: a quantity expressed as a fraction of a chosen base value (1.00 pu = nominal voltage or rated power), the standard language of power-system studies.
Why it matters: It lets a 0.4 kV LV board and a 110 kV network be compared on one axis and one chart. Voltage 0.95–1.05 pu is the usual acceptance band, so any per-unit figure in a report can be read directly against the criterion.
Loading: the current (or power) carried by a branch expressed as a percentage of its rated capacity.
Why it matters: It is the acceptance number for cables and transformers. Above 100 % the element will trip or have to be derated, and the margin left at the design case is exactly what the customer is paying for — so it must be shown with the assumption (load factor, ambient temperature) that produced it.