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Busbar

Load flow analysis busbar connector

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  • Busbar block

Libraries:
Simscape / Electrical / Connectors & References

Description

The Busbar block is a connector for load-flow analysis. Use this block with three-phase Simscape™ Electrical™ networks that are compatible with frequency-time simulation mode. After completing simulation, the block adds an annotation showing the voltage, phase, active power, and reactive power at each of its three-phase electrical conserving ports at the time the simulation started. For the annotation to be added, Simscape logging must be enabled.

The block will simulate in time-based simulation mode, however it will not add the annotation with initial load flow results unless the network is compatible with frequency-time simulation mode and, on the Solver Configuration block, you check Start simulation from steady state. However, when using time-based simulation mode, the block calculates approximate values for voltage, phase, active and reactive powers. You can view these values from Simscape logging or by exposing the optional measurement ports on the block. The level of approximation depends on how balanced the system is and on the level of harmonics present.

Examples

2-Bus Loadflow

2-Bus Loadflow

A model of a two-bus three-phase power system network. The model uses three instances of the Load Flow Source block from Simscape™ Electrical™, one configured to be the swing bus, one configured to be the PV bus, and one configured to be the PQ load. The PV bus regulates its output to be at a voltage of 1.025 times rated voltage and to deliver 80MW active power to the network. The Swing bus regulates voltage at the other end of the transmission line to be one times rated voltage, and it delivers the requisite power to the network so that overall active and reactive powers balance. The Simscape initialization solver determines the required internal initial voltage amplitudes and phases in both the PV bus and the Swing bus so as to start in steady state.

IEEE 9-Bus Loadflow

IEEE 9-Bus Loadflow

A model of a 9-bus three-phase power system network. This example is based on an IEEE® benchmark test case, further details of which can be found in "Power System Control and Stability" by P. M. Anderson and A. A. Fouad (IEEE Press, 2003). Simscape™ initializes two of the generators to the specified powers and terminal voltages, and initializes the remaining swing bus generator to meet just the specified voltage. The resulting load flow solution is appended to each of the busbars post-simulation. The four rows correspond to per-unit voltage, phase, active power, and reactive power respectively. Looking at Bus 1, it can be seen from the annotation that the swing generator delivers 76.4MW of active power and 27.5MVAr or reactive power to the network. Differences to the original benchmark are due to the transmission line models and transformer configurations used.

Induction Motor Initialization with Loadflow

Induction Motor Initialization with Loadflow

Initialize a three-phase induction motor as part of a load flow analysis. When initializing an induction machine that is directly connected to an AC network, in steady state there is one degree of freedom which you can set by any one of shaft torque, shaft power, motor speed, or electrical power.

Synchronous Machine Initialization with Loadflow

Synchronous Machine Initialization with Loadflow

Initialize synchronous machine as part of a load flow analysis. When initializing a synchronous machine there are two degrees of freedom which can be set by any two of rotor angle, active power, reactive power and terminal voltage. The pair of variables that are constrained is set by the source type drop-down menu, this having options of Swing bus, PV bus and PQ bus. Here the machine is configured for a swing bus with a 1.02 per-unit voltage and zero degrees phase.

IEEE 9-Bus System

IEEE 9-Bus System

Model a 9-bus three-phase power system network. This example is based on the IEEE® benchmark test case. For more information, see "Power System Control and Stability" by P. M. Anderson and A. A. Fouad (IEEE Press, 2003)

Ports

Output

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Physical signal port associated with the voltage measurement. The value is reported in per-unit, i.e. phase-to-phase root mean square voltage divided by the Rated busbar voltage (phase-to-phase RMS).

Dependencies

This port is visible only when, in the Parameters settings, the Measurement ports parameter is set to Yes.

Physical signal port associated with the voltage phase measurement.

Dependencies

This port is visible only when, in the Parameters settings, the Measurement ports parameter is set to Yes.

Physical signal port associated with the active (real) power measurement.

Dependencies

This port is visible only when, in the Parameters settings, the Number of connections parameter is set to 2, 3, or 4 and the Measurement ports parameter is set to Yes.

Physical signal port associated with the reactive (imaginary) power measurement.

Dependencies

This port is visible only when, in the Parameters settings, the Number of connections parameter is set to 2, 3, or 4 and the Measurement ports parameter is set to Yes.

Conserving

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Composite three-phase electrical conserving port associated with the first three-phase connection.

Composite three-phase electrical conserving port associated with the second three-phase connection.

Dependencies

This port is visible only when, in the Parameters settings, the Number of connections parameter is set to 2, 3, or 4.

Composite three-phase electrical conserving port associated with the third three-phase connection..

Dependencies

This port is visible only when, in the Parameters settings, the Number of connections parameter is set to 3 or 4.

Composite three-phase electrical conserving port associated with the fourth three-phase connection.

Dependencies

This port is visible only when, in the Parameters settings, the Number of connections parameter is set to 4.

Parameters

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Number of port connections that are exposed on the block.

The number of exposed ports on the block correlates to this parameter.

Rated phase-to-phase root mean square voltage of the busbar.

Frequency of the connected network.

Visibility for the voltage, phase, active power, and reactive power physical signal output measurement ports.

Dependencies

Ports Vt and ph are visible only when this parameter is set to Yes.

Ports P and Q are visible only when this parameter is set to Yes and, in the Parameters settings, the Number of connections parameter is set to 2, 3, or 4.

Extended Capabilities

C/C++ Code Generation
Generate C and C++ code using Simulink® Coder™.

Version History

Introduced in R2019b

See Also

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