🏭Power Grid Simulator - High Voltage, HVDC, Dispatch, Frequency Stability

How to use Power grid simulator

1. 1In Why high voltage, enter power and distance and pick a voltage level to compare current, loss and voltage drop
2. 2In AC vs HVDC, choose an overhead line or a submarine cable, adjust capacity and distance, and find the breakeven point
3. 3In Daily load & dispatch, set the capacity of each source or drag the load on the chart to see the duck curve, curtailment and storage
4. 4In Frequency stability, pick a preset or set inertia, droop and reserve to see the nadir, RoCoF and load shed
5. 5In Three-phase and Transformer & PF, adjust phase currents, turns ratio and power factor

FAQ

Why is electricity transmitted at high voltage?

For a given power P, three-phase line current is I = P/(√3·V·cosφ), inversely proportional to voltage, while line loss is 3I²R, proportional to current squared. Raise the voltage tenfold and the current drops to 1/10 and the loss to 1/100. Sending 1000 MW over 300 km loses over 30% at 220 kV, about 2.4% at 500 kV and only about 0.2% at 1000 kV UHV. Voltage cannot rise without limit, because insulation, towers, substations and corona loss all get more expensive, so each level suits certain distances and capacities.

When is HVDC cheaper than AC?

A DC line needs only two conductors and has no reactance or capacitive charging current, so it costs less per km, loses less, and has no synchronous stability limit. But each end needs an expensive converter station with about 1.5% conversion loss. The longer the line, the more the cheaper line saves, and beyond the breakeven distance DC wins. For overhead lines that is typically 600–800 km; for submarine or underground cables, where AC charging current is huge, DC pays off after a few tens of km. Costs in the tool are a relative teaching model you can adjust.

What is the duck curve, and how does storage help?

Subtract wind and solar output from demand and you get the net load. It sags at midday when solar peaks and then shoots up in the evening as the sun sets and demand rises, tracing the shape of a duck. Other plants must ramp up steeply within two or three hours, and if they cannot turn down far enough at midday, solar is curtailed. Storage saves the midday surplus and releases it at the evening peak, cutting curtailment and gas peaker use. The tool dispatches nuclear, wind/solar, storage, hydro, coal and then gas so you can see these effects directly.

What happens to grid frequency when a generator trips?

At first the missing power can only come from the kinetic energy stored in every synchronous rotor, so frequency starts to fall at RoCoF = ΔP·f₀/(2H·S): the lower the inertia H, the faster. Within seconds governors raise output (primary control), the frequency turns at its nadir and settles slightly below nominal, offset by about ΔP/(1/R + D). AGC then restores 50 Hz over minutes. If frequency falls to around 49 Hz, under-frequency relays shed load automatically to prevent a blackout, as happened in Great Britain in August 2019.

Why does three-phase power need only three wires?

Three-phase power uses three sine voltages 120° apart. With a balanced load the three currents add to zero at every instant, so no current flows in the neutral and it can be omitted. For the same power, line voltage and loss, a three-phase three-wire system needs only 75% of the copper of a single-phase two-wire system. The total instantaneous power is constant, so motor torque is smooth, and a rotating magnetic field comes naturally. For real and reactive power and power factor in a single circuit, use the AC power tool.