Water and Power Associates Informing the Public about Critical Water and Energy Issues facing Los Angeles and California

Historical Notes

Before the advent of remote control and monitoring equipment, substations had to be manned (and until the 1970’s Operators were exclusively men) twenty four hours a day. The Operators would control, operate, and maintain the electrical components within the station to ensure proper voltage regulation and reliability in the surrounding service area.  Today, the majority of these stations are automated and operated remotely.

Before World War II, almost all the Bureau of Power and Light Distributing Stations were continuously attended; a handful of small stations, located in remote areas were operated by early supervisory equipment from nearby attended stations.

Historical Notes

The Operators were primarily responsible for the routine and emergency operation of the station’s equipment.  The most important duties involved testing circuits after they had “relayed” (their circuit breakers opened by operation of protective relays to clear a fault in the field).   They might also have to respond to trouble involving equipment in the station to restore power or avoid damage to the equipment. 

Historical Notes

Distributing Stations transfer power from the transmission system to the distribution system for a specific service area. It is uneconomical to directly connect electricity customers to the main transmission network, unless they use large amounts of power. Therefore the distribution station reduces voltage to a value suitable for local distribution. In addition to transforming voltage, the substations regulate voltage which ensures a smoother level of power as seen by the customer.

Historical Notes

A synchronous condenser (sometimes called a synchronous capacitor or synchronous compensator) is a device identical to a synchronous motor, whose shaft is not connected to anything but spins freely. Its purpose is not to convert electric power to mechanical power or vice versa, but to adjust conditions on the electric power transmission grid. Its field is controlled by a voltage regulator to either generate or absorb reactive power as needed to adjust the grid's voltage, or to improve power factor.*^

Historical Notes

The use of rotating synchronous condensers was common through the 1950s. They remain an alternative (or a supplement) to capacitors for power factor correction because of problems that have been experienced with harmonics causing capacitor overheating and catastrophic failures. Synchronous condensers are also useful for supporting voltage levels.*^

Historical Notes

Many stations had manually controlled streetlight circuits that had to be turned on and off according to a schedule.  Transformer temperatures were monitored for signs of overheating as were synchronous condensers and converters in the stations where they were installed.  They also monitored and recorded the load on the transformer banks 34.5-kV circuits and 4.8-kV feeders and kept their portion of the station clean and neat.

Historical Notes

The streetlight equipment was on the balcony at DS-3; in most stations it was in the basement.  Closest is the Streetlight Test Panel, beyond that are the streetlight transformers, usually called "tubs." 

Historical Notes

Series streetlights were often troublesome and in attended stations, each circuit was tested twice a day, once at noon and again before streetlight on time.

Historical Notes

On the PM shift one of the first things to do after coming on shift was to check the Streetlight Schedule to determine the time they were to be turned on.  At "streetlight on time" the Operator would close the circuit breaker to energize the Streetlight Bus and then call the Load Dispatcher to report them on.  Due to the number of calls the Load Dispatcher would be receiving, all at the same time, the conversation was very abbreviated:  the Operator would report "On at 3" and the Dispatcher would acknowledge "3 on" and go on to his next call.

Historical Notes

When the majority of stations were attended, manpower requirements were significant; into the early 1950’s there were over 1000 DWP Power House and Station Operators (as they were then known) working in Receiving and Distributing Stations and hydro power plants.  Operators began their careers as Assistant Operators, assisting with the work in the larger stations and learning the trade.  They could then take the Civil Service exam to be promoted to Operator.  As an Operator, they would usually start off working by themselves in a small larger Distributing Station.  As their seniority accumulated, they could bid shifts in the larger stations.  The top of the seniority ladder in a Distributing Station was the Senior Operator, who worked the weekday day shift and, as a lead worker, was two pay grades higher than the other Operators.

Historical Notes

The attended Distributing Stations were converted to supervisory control, beginning in the early 1950’s, with the last one going on supervisory control in the 1980’s.  Today they are all controlled by Remote Terminal Units from the Energy Control Center.^^