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The Power System Toolbox consists of 3-phase components for power system studies (short circuit and fault analysis and relay protection). Key elements are the LINE3 component that are drawn and edited like Connections and the various phasor calculators based on MODELS.
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Fundamental components
These are the building blocks in power system studies with easy fault application. Combine this with the standard voltage and current probes with steady-state output.
Selection |
Object name |
Icon |
ATP card |
Description |
Bus |
BUS3 |
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BRANCH |
Multi-node (Bays) connection point with optional load and arrester. |
Line |
LINE3 |
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BRANCH |
LINEPI3S or LINEZT_3 component with faults, CB and CT. Edited like Connections. |
Load PQ |
LOADPQ |
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MODELS RLC+SRC |
Voltage dependent load model. Group with MODELS controlled source based on phasor calculation |
Ctrl CB |
CTRLCB |
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MODELS SWITCH |
3-phase TACS switch, opens at MODELS controlled zero crossing |
Basic MODELS calculators
These calculators takes in 3-phase current or voltage chosen in the input node (left) dialog box.
Selection |
Object name |
Icon |
ATP card |
Description |
RMS |
ABC2RMS |
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MODELS |
Outputs RMS value of all 3-phase inputs |
Phasors +Basic |
ABC2PHR |
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MODELS |
Outputs phasors (re, im) for all 3-phase inputs. DFT recursive or FFT methods with down sampling. |
Phasors +Initialized |
ABC2PHRI |
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MODELS |
Same as ABC2PHR but with steady-state initialization at t=0 |
Phasors +Freq. variant |
ABC2PHRF |
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MODELS |
Same as ABC2PHR but with frequency as input (from PLL) |
Phasors +1+h |
ABC2PHRH2 |
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MODELS |
Calculate phasors (re, im) in fundamental frequency and one extra harmonic. |
Phasors +Sequence 012 |
ABC2SEQ |
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MODELS |
Calculate phasors and convert it to sequence 012 output (re, im). |
Phasors +Write/Plot |
WRITEPHASOR |
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MODELS |
Takes in phasors (re, im) to View this at specific instance in time |
Filters +Low pass |
BLPFILT |
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MODELS |
0-3 order Butterworth low pass filter with gain adjustment |
Filters +High pass |
BHPFILT |
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MODELS |
0-3 order Butterworth high pass filter with gain adjustment |
PLL |
PLLDQ |
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MODELS |
Calculation of frequency based of park transform of 3-phase inputs |
Harmonics |
HARMONICS |
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MODELS |
Calculation of 1-26 harmonics based on DFT recursive alg. Old. |
Power and RX calculators
These calculators require input of 3-phase currents and voltages (top-left node is voltage, bottom-left node is current). Normally the two input nodes can simply be connected and further to a unique 3-phase switch node, as shown in Fig. 4.86 . Note that currents can only be obtained from switches and ATP will give you the current in the first switch connected to the node you specify. To make sure you get the correct current in the case of several switches connected to the same bus, you should connect to a node not shared by any other switch with a different current. The current probe with Add current node adds two measuring switches in series behind the scene and gives you access to the unique middle point.
Selection |
Object name |
Icon |
ATP card |
Description |
PQ +PQ 3*1 |
UI2PQ |
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MODELS |
Calculate active and reactive power per phase for 3-phase volt and curr. |
PQ +PQ 3-phase |
UI2PQ3 |
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MODELS |
Calculate active and reactive 3-phase power. DFT+FFT+DQ alg. |
PQ +Watt meter |
WMETER |
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MODELS |
Calculate average active power by integral method. No downsampl. |
RX + (Ua-Ub)/(Ia-Ib) |
UI2RXL |
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MODELS |
Calculation of positive sequence impedance (R, X) for phase-to-phase faults. |
RX + (Ua-Ub)/(Ia-Ib) |
UI2RXE |
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MODELS |
Calculation of positive sequence impedance (R, X) for phase-to-ground faults. |
RX +Ua/Ia |
UI2RX |
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MODELS |
Calculates the impedance seen in each phase |
Protective relays
These relays should be connected to RMS (over current, and under/over voltage), Phasor calculators (differential), and RX calculators (distance). The directional over-current relay has its own zero sequence phasor calculator, and the frequency relay requires frequency input. The user must click on the input node of the models to make sure the correct signals are recorded. The relays using signals from other models has default input from models and must be ordered after the model producing the signals. Sorting by order was previously the only option to accomplish this, but ATPDraw v7 offers an option Edit|Arrange|Sort all Models to help ordering correctly. All the relays has a blocking control signal input, trip signal and trip zone information outputs. In the dialog window the user sets the zone characteristics and there is also View option that plots the zones and recorded trajectories (with down sampling) until trip. The W1RELAY21P component also has a zone helper.
Selection |
Object name |
Icon |
ATP card |
Description |
Relays +Overcurrent 50/51 |
W1RELAY51 |
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MODELS |
Based on rms input and a definite time zone gives a trip signal out. Blocking option available. Zone output not relevant. |
Relays +Time over-current |
W1RELAY51I |
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MODELS |
Based on rms input and standardized inverse time zone gives a trip signal out. |
Relays +Dir. Ground 67N |
W1RELAY67N |
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MODELS |
Current and voltage input with internal zero sequence phasor calculation. Trips is |V0|>Vlim and I0 in zone relative to V0. |
Relays + Distance quad 21 |
W1RELAY21P |
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MODELS |
Input from RX calculator. Three delayed zones with 4 points. Zone helper available. |
Relays + Distance circ 21 |
W1RELAY21C |
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MODELS |
Input from RX calculator. Three delayed zones with mho characteristic. |
Relays +Diff transf. 87T |
W1RELAY87T |
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MODELS |
Input from current phasors 1+h. Calc. differential current with turns ratio, phase shift scaling and harmonic blocking (inrush). Current into unit on both sides. |
Relays +Diff line 87L |
W1RELAY87L |
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MODELS |
Input from current phasors 1+h. Calc. differential current with time delay compensation and harmonic blocking. Current into unit on both sides. |
Relays +Under-voltage 27 |
W1RELAY27 |
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MODELS |
Input from rms voltage. Two undervoltage zones with time delays and 3 different standard characteristics. |
Relays +Over-voltage 59 |
W1RELAY59 |
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MODELS |
Input from rms voltage. Two overvoltage zones with time delays and 3 different standard characteristics. |
Relays +Frequency 81 |
W1RELAY81 |
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MODELS |
Input from frequency calculator. Two zones for both under and over frequency with fixed time delay. |
TACS
Selection |
Object name |
Icon |
ATP card |
Description |
TACS +RMS |
TABC2RMS |
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TACS |
3-phase RMS calculator. DEVICE66 |
TACS +Freq |
TABC2FRQ |
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TACS |
3-phase frequency calculator. DEVICE50 |
TACS +DQ0 |
TABC2DQ0
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TACS |
3-phase park transform calculator. |
TACS +alpha-beta |
TABC2ABG |
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TACS |
3-phase alpha-beta transform calculator. |
