Generator–Grid Dynamics Studio

Generator–Grid Dynamics Studio

One operating point · stability, controls, flexibility, harmonics and grid code

InputsSMIB

Operating point

Plant rating, MW Active power P, MW Reactive power Q, MVAr Infinite-bus voltage, pu Frequency, Hz

Machine + grid

X′d, pu Transformer X, pu Grid equivalent X, pu Inertia H, s Damping D, pu

Disturbance

Fault transfer, % Clearing time, ms Post-fault grid X × Simulation, s

Model: classical generator, constant E′, lumped transfer reactance and RK4 swing-equation integration.

4th-order machine

X_d, pu X_q, pu X′_q, pu T′_do, s T′_qo, s

X′d is shared with the classical model on the Stability tab.

AVR / exciter

Enabled

K_A T_A, s E_fd,min, pu E_fd,max, pu

Governor + turbine

Enabled

Droop R, pu/pu T_g, s T_t, s

PSS

Enabled

K_PSS T_w, s T₁, s T₂, s |V_PSS| max, pu

Model: 9-state SMIB: rotor, transient d/q EMFs, first-order AVR, governor+turbine and washout/lead-lag PSS. The fault uses the disturbance data from the Stability tab.

Network study

Network preset System base, MVA Disturbance Event at, s Simulation, s N−1 / post-fault branch

Fault setup

Fault bus Faulted line Line position, % from A R_f, pu X_f, pu Clearing sequence First side First clearing, ms Second clearing, ms Monitor bus FRT envelope

Line faults use an explicit virtual fault node. Sequential clearing keeps the fault fed from the remote end until the second breaker opens.

Generators + controls

Lines / transformers

Bus loads

not run

Model: 2–4 transient-EMF machines in a balanced AC Y-bus with R+jX branches, transformer tap/phase shift, Z/PQ/frequency-sensitive loads and reduced per-machine AVR/PSS/governor. Disturbances include N−1 trips and three-phase bus/line faults with explicit clearing stages.

Primary source dynamics

Plant type Minimum load, % Maximum load, % Ramp up, MW/min Ramp down, MW/min Plant response delay, s

Fast resource / BESS

Power, MW Full response, s Energy, MWh Initial SoC, %

Grid request

ΔP, MW Response target, s Sustain target, min

Plant presets are editable illustrative starting values. Use project/vendor values for an actual unit.

Grid equivalent at PCC

Voltage, kV Short-circuit power, MVA X/R Capacitor bank, MVAr Shunt reactor, MVAr Fundamental current, A

Injected harmonic currents, % I1

h = 5 h = 7 h = 11 h = 13

Balanced linear frequency scan; transformer/cable frequency dependence and converter control impedance are not yet modelled.

Grid-code pack

Load JSON pack

The calculation code is separate from operator requirements. Packs can carry authority, jurisdiction, status, validity dates and requirement IDs; only supported requirement types are evaluated.

Challenge mode
Each task changes the same engineering model. Solve it with the normal controls, then press “Evaluate”.

Transient stability

ready

Rotor angle δ

—

initial

Critical clearing

—

classical SMIB

Equal-area margin

—

pu·rad

Outcome

—

—

Time response

P–δequal area

PhasorsV · I · E′

P–Q capability—

Detailed transient

—

—

Dominant mode

—

Hz

Damping ratio ζ

—

—

Terminal voltage

—

pu

Detailed dynamic response

Eigenvalue planelinearized at operating point

Controller chainAVR · GOV · PSS

—

Eigenvalues are obtained from a numerical Jacobian of the same nonlinear equations at the pre-fault equilibrium.

Active machines

—

2–4

Disturbance transient

—

—

Critical mode

—

—

Damping ratio ζ

—

—

Minimum monitored voltage

—

I_fault,peak — pu

Voltage recovery

—

s after clearing

Frequency nadir

—

—

Reactive-current peak

—

—

Editable network · click a line to select the contingencyY-bus

Relative rotor angles after N−1—

Bus voltages / FRT envelope—

Frequency responseCOI

Reactive-current responseΔIq

Post-contingency eigenmodesδ · Δω

Critical mode shape—

Electromechanical modescoherent groups

Batch N−1 screeningnot run

Run the batch study to rank every in-service branch contingency.

Upward reserve

—

MW

Downward reserve

—

MW

90% response

—

s

Sustain

—

—

Fast-resource → plant handover—

Flexibility envelopeΔP · response · sustain

Resonance peak

—

Hz

Peak |Z|

—

Ω

THDᵥ

—

%

Nearest harmonic

—

—

Driving-point impedance scan|Z(f)|

Resulting harmonic voltageh = 5, 7, 11, 13

Evaluated

—

requirements

PASS

—

—

FAIL

—

—

Unsupported

—

not evaluated

Capability vs requirementexample