In the multi-infeed HVDC system, the interaction between inverter stations is an important factor that triggers the propagation of commutation failure. This paper aims to study the interaction mechanism of invert.
A unique property of inverter-based DER is the power electronics interface. Power electronics have the ability to control fault current contributions from DER systems. This adjustability can thereby optimize the system protection coordination issues by controlling fault current levels (Tang and Iravani 2005).
When does a yd inverter fail to commutate?
When the commutation first occurs in the YY inverter, it's assumed that the commutation failure first occurs in the commutation of V12 to V32. Since the short-circuit path is formed when V42 is conducted, the YD inverter will fail to commutate during the commutation of V21 to V41. The commutation process is shown as Fig. 7 (a).
What does a blue trace on an inverter mean?
The light blue trace represents the line voltage and the purple trace represents the inverter AC fault current. Typically, the inverter manufacturer will perform a short-circuit test by using a contactor device that will close and create the short-circuit event.
Power electronic inverters have a much faster decaying envelope for fault currents because the devices lack predominately inductive characteristics that are associated with rotating machines. These characteristics dictate the time constants involved with the circuit.
What are inverter-based der?
Typically, inverter-based DER are designed to act as ideal current sources. Therefore, they provide minimal fault current contributions and have little effect on overcurrent protection and coordination strategies for fuse and circuit breakers (General Electric 2003).
Do power electronic inverters develop inertia?
Inverters do not have a rotating mass component; therefore, they do not develop inertia to carry fault current based on an electro-magnetic characteristic. Power electronic inverters have a much faster decaying envelope for fault currents because the devices lack predominately inductive characteristics that are associated with rotating machines.