The key difference is that IEC 60909 is for land-based, 50 Hz and 60 Hz power systems up to 550 kV, while IEC 61363 specifically addresses short-circuit studies for marine and offshore installations, which have unique characteristics.
Here's a breakdown of the differences:
IEC 60909: Short-circuit current calculation in three-phase AC systems
- Scope: Applies to the calculation of short-circuit currents in three-phase AC power systems operating at 50 Hz or 60 Hz. Voltage levels are up to 550 kV.
- Application: Primarily intended for land-based power systems.
- Focus: Provides methods for calculating short-circuit currents for various fault locations and system configurations.
- Generator and Motor Modeling: Uses simplified, standardized models for generators and motors contributing to the short-circuit current.
IEC 61363: Electrical installations of ships and mobile and fixed offshore units - Electrical design
- Scope: Specifically designed for electrical installations on ships, mobile offshore units, and fixed offshore units. This includes power generation, distribution, and utilization.
- Application: Focused on the unique challenges and characteristics of marine and offshore environments.
- Focus: Addresses short-circuit calculations within the context of overall electrical design for these specialized environments. It represents conditions that may affect typical marine or offshore installations more significantly than land-based systems
- Generator and Motor Modeling: Places more emphasis on the transient behavior of generators and motors during short-circuit conditions, particularly the decay of their contribution to the fault current. This is crucial in systems where generators often operate in parallel with limited capacity. Marine and offshore systems often have a significant portion of fault current contributed by motors, requiring accurate modeling.
Table Summarizing the Key Differences:
| Feature | IEC 60909 | IEC 61363 |
|---|---|---|
| Application | Land-based power systems (50/60 Hz, up to 550 kV) | Marine and offshore electrical installations |
| Environment | General | Specialized (ships, offshore platforms) |
| Generator/Motor Modeling | Simplified, standardized models | More detailed models with emphasis on transient behavior and decay characteristics, crucial for accurate calculations in limited capacity systems. |
| Emphasis | General short-circuit calculations | Short-circuit calculations within the context of overall electrical design considering unique marine/offshore conditions. |
In essence, while both standards deal with short-circuit calculations, IEC 61363 tailors the calculation methods and modeling assumptions to better reflect the specific operating conditions and design considerations of marine and offshore electrical systems. The greater emphasis on generator and motor decay reflects the differences in system architecture and equipment typically used in these environments.
