The time periods

There are three over all time periods that a power system study will look at, they are:

• Transient
• Dynamic
• Static

Transient studies look at the over all power system response to an event over a very short period of time. This time period can be from a portion of a cycle to 1 or 2 seconds. An example of a transient study would be analyzing the system response of a capacitor bank being switched on to the system, and verifying that it won't introduce an instability.

Dynamic studies look at the power system response over seconds to a minute until the system has reached a new steady state. An example of a dynamic study is starting a large motor, line an ID Fan. Motors have high starting currents and can have major impacts on the system voltage.

Static studies review the system in a steady state and is used to report the values. Load Flows, also referred to as Power Flow studies are good examples of this. They are used to determine the voltages, currents, and power factor at all the buses and cables within the power system.

Studies includes in the Power System Analysis

There are many different studies that can be included in a Power System Study report, a few of the more common are:

• Short Circuit
• Protection Coordination
• Incident Energy
• Load Flow
• Dynamic Motor Starting
• Transient Stability
• Power Quality
• Harmonic Analysis

They all have a place in the report, but some are more used than others, for example the four studies that I recommend that all facilities have are:

• Short Circuit
• Protection Coordination
• Incident Energy
• Load Flow

With these studies a facility will have most of the information required to troubleshoot problems, control change management, improve operation, make better maintenance and capital decisions just to name a few.