BGE Loss Factors

Losses naturally occur as a result of transporting electricity from power plants to the points of utilization. These losses vary with the location and magnitude of the load, as well as with voltage level, equipment type, wire size, configuration and the location of generation. There are also ’no-load’ losses associated with energizing transformers.

BGE’s loss determination method utilizes a combination of widely accepted network analysis techniques and approximated values to calculate losses. The method is composed of three basic steps as follows.

  1. Losses associated with the bulk transmission and sub-transmission systems are determined using Power Technologies, Inc.’s PSS/ET package, based upon historical load and generation patterns. The losses, which vary with system loading conditions, as well as transformer no-load losses, are allocated to customers connected at the 230kV, 115kV, 34.5kV and 13.8/4kV portions of the system, based on the total load at that voltage. This apportionment technique is similar to PJM’s approach to allocating 500kV losses.
  2. Distribution line losses are approximated using PTI’s PSS/U package. These losses are allocated between primary and secondary connected customers using the system average customer load connected for the respective customer classifications.
  3. Losses associated with energizing distribution transformers, as well as losses resulting from distribution transformer loading, are approximated using transformer manufacturers’ data and average transformer loading information for the system. Losses associated with loads on secondary and service connections are approximated using data based upon system averages.

Losses associated with through flow are compensated through the PJM guidelines and procedures.

Resulting loss factors are estimated as follows. (These loss factors do not include losses associated with Unaccounted For Energy)

Voltage Class Loss Factor
Primary Voltage  
230 kV 0.878%
115 kB 1.622%
34 kV 2.473%
13 and 4 kV 3.660%
Secondary Voltage 6.665%