CAPACITOR OPERATION AND MAINTENANCE

CAPACITOR OPERATION AND MAINTENANCE

Basic operation and maintenance of capacitor in distribution system

Capacitors on distribution lines must be kept operational if their benefits are to be retained. Lightning surges or other disturbances occasionally cause capacitor fused cut-outs to open, and the distributor should promptly check and refuse such units to keep all capacitors operational. Care should always be taken in refusing capacitor units, since energizing units that have been damaged internally often results in capacitor case failure.

Since no consumer complains when a capacitor cut-out opens, some distributors might delay returning the capacitor to service. However, such delays are costly to the distributor because of increased line losses and possible wholesale power factor surcharges.

Switched capacitors need to be checked periodically to ensure proper operation of switches and controls. Operation counts should also be recorded. A large or small number of operations may indicate that settings need to be modified.

Capacitors and PCBs

Capacitors installed prior to 1977 may have been manufactured with a dielectric fluid containing PCBs. Distributors with such units on their systems should immediately remove and properly dispose of them. To continue receiving the benefits from capacitor installations, the distributor should replace removed units with modern non-PCB units. Instead of simply changing units one by one, however, distributors should perform studies under a coordinated engineering plan to update capacitive requirements for all system feeders.

Utilization Voltage Capacitors

Another possible location for capacitors that should not be overlooked is at the utilization voltage level at consumer equipment supply buses. This location may be practical for some commercial and industrial consumers. Since these capacitor locations lie beyond the meter, the consumers themselves would purchase and install these capacitors. The distributor’s role is to apply commercial and industrial retail rate riders that provide incentive for consumers’ installation of capacitors, such as power factor penalty provisions. Special rate riders are required to be approved by TVA.

Coordination with Consumers

Capacitors installed at utilization voltage levels offer the added advantage of reducing currents in distribution transformers and secondary lines. To facilitate reduction of these currents and their associated losses, distributors should apply rate riders, as approved by TVA, which encourage consumers to install capacitors. Distributors might also consider a program that would provide technical assistance and advice to consumers wishing to purchase and install capacitors.