Reliability By Design

Station power reliability (continuity and quality) is a result of systems planning and design, as well as equipment design and quality.

Three basic configurations are used to ensure station power reliability:

Solution A:
Critical DC Power

AC-DC converters (rectifiers), batteries and DC-DC converters.

Solution B:
Critical AC Power

Two AC sources including a generator and / or UPS with prime power.

Solution C:
Critical DC & AC Power

Hybrid of A and B with critical DC power feeding line redundant, on-line or standby inverter(s) (DC-AC).

  • Solution A is a standard and cost-effective telecom and utility station, DC power solution
  • Solution B is a standard AC power solution used in many industrial and commercial applications, especially those requiring dedicated, computer backup power.
  • Solution C is used in industrial and utility applications, such as power stations, having both critical DC and AC power requirements.
Staticon rectifier, inverter, UPS and line conditioner products are often specified for all of these configurations.

Bear in mind that generally, unit equipment reliability decreases as its electronic sophistication and number of components increases. This fact is the basis for the widely used parts-count reliability assessment methods originally developed by the military and now used in many industries. Equipment field serviceability also decreases with increasing complexity.

Staticon power conversion equipment designs are based on natural convection cooling, magnetic control and a minimum of electronic modules rendering them optimally reliable, accessible and field serviceable.

Redundancy is the provision of multiple sources or units of equipment to provide backup capability in the event of unit source or equipment failure.

Redundancy enhances power system reliability by bridging prime power outages and unit equipment repair periods.

Parallel redundancy is the use of multiple units of active, on-line, energized power supply equipment. There is no switching of any sources / equipment involved. Parallel redundancy results in the sharing of load between active units of power conversion equipment.

Standby redundancy is the use of alternate power source / equipment units that are switched in to supply load power during prime power or on-line equipment failure

Warm standby redundancy is the use of energized, alternate power source / equipment that is unloaded (idle) until the load is switched over to it.

Cold standby redundancy is the use of de-energized, alternate power sources and / or equipment that is unloaded until the load is switched over to it.


Fundamental principles apply to the design of redundant, critical station power systems:

  • Station power system reliability as well as cost, weight and physical size increases with increasing redundancy. The system MTBF (mean time between failures) increase is greatest when the number of redundant paths increase from 1 to 2.
  • As beneficial as redundancy is, it also results in an increased source or equipment failure risk (a result of using more sources or units of equipment). To reduce this risk, it is essential to choose the most reliable and therefore cost-effective power system equipment.
  • Components, switchgear or connections common to a system of redundant sources / equipment reduce system reliability due to common-mode system failure possibilities. Common-mode items should be eliminated or minimized.
  • Full power, on-line, parallel redundancy exists when redundant equipment units can supply full load, otherwise only partial redundancy exists.
Staticon power equipment modules have a very high MTBF due to their rugged design and provide maximum redundancy with a minimum of common-mode failure possibilities.