The content of this article is the reference "Graphical Simulation Technology of Electrical Control System Based on MATLAB"
The previous article introduced some modules of the power system. This article simulates examples to gain a deeper understanding and use of these modules.
Simulation content includes:
1. Power failure simulation
2. Transformer performance simulation
3. Power Transformer Fault Simulation
4. Power system transmission performance simulation
5. Fault simulation of small current grounding system
1. Power failure simulation
1.1 Three-phase short-circuit fault simulation of infinite power supply system
1.1.1 Three-phase short-circuit electrical principle of infinite power supply system
Assuming that the magnitude and frequency of the power supply voltage are constant, this kind of power supply is called an infinite power supply . In this case, the short circuit of the external circuit has little effect on the power supply, and it can be approximately considered that the amplitude and frequency of the power supply voltage remain constant.
The circuit is composed of a high-power power supply S, a power transformer T, a transmission line L, and a three-phase series RLC load.
1.1.2 Modeling of the circuit
For specific simulation parameter design, please refer to "Graphic Simulation Technology of Electrical Control System Based on MATLAB"
1.2 Simulation of sudden short-circuit fault of synchronous generator
1.2.1 Electrical characteristics of sudden short-circuit fault of synchronous generator
In case of a sudden short circuit, the stator current changes rapidly in value, and the armature reaction flux also changes accordingly, and an induced current is generated on the rotor winding, which in turn affects the change of the stator current. The interaction of stator and rotor winding currents is a remarkable feature of the sudden short-circuit transient process of synchronous generators.
1.2.2 Modeling of the circuit
2. Transformer performance simulation
2.1 Single-phase transformer simulation
2.1.1 Simulation of no-load operation of single-phase transformer
2.1.2 Simulation of single-phase transformer load operation
2.2 Three-phase transformer simulation
2.2.1 Three-phase transformer no-load operation simulation
2.2.2 Three-phase transformer load operation
2.3 Three-phase transformer connection group simulation
2.3.1 Three-phase transformer connection group Yd11 simulation
30 degrees out of phase.
2.3.2 Simulation of three-phase transformer connection group Yy6
180 degrees out of phase.
2.3.3 Three-phase transformer connection group Yy4 simulation
The difference is 120 degrees.
2.3.4 Three-phase transformer connection group Yy0 simulation
Almost in phase.
3. Power Transformer Fault Simulation
3.1 Simulation of power system circuit faults of double-winding transformer with double-sided power supply
3.2 Simulation of three-phase short-circuit fault on the secondary side of the transformer
3.3 Simple Simulation of Internal Faults in Transformer Windings
4. Power system transmission performance simulation
Transmission lines have two important characteristics, characteristic impedance and time delay . In the module library, Line has three types: PI Section Line module, Distributed Parameters Line and RLC branch. The following takes the transmission of the high-frequency DC signal output by the Boost DC chopper in the power transmission line as an example to simulate the power transmission performance.
4.1 Circuit simulation without transmission line module
4.2 Circuit simulation with transmission lines
5. Simulation of small current ground fault
5.1 Simulation of neutral point ungrounded system
5.2 Simulation of neutral point through arc suppression coil grounding system
Write it at the end. The purpose of simulation is to be familiar with the use of each module and the process experience of simulation. Don't be intimidated when faced with new simulation tasks. For detailed parameters, refer to " Graphical Simulation Technology of Electrical Control System Based on MATLAB "