AC Voltage Systems, Transformers and the Electrical Power Monitoring System (EPMS)


Electricity in the modern world is something for the most part is unseen and at the same time taken for granted that is will be there when needed. This unseen force is produced and used daily and has dramatically changed the ways people live their lives. Let’s take a look at the AC Voltage Systems most commonly used and the equipment that makes it usable to all.

Alternating Current (AC) voltage systems can be separated into several categories. A control voltage distribution systems will range from 0-49 VAC. This would be used typically a signaling voltage to control a higher voltage. A low voltage distribution system will range from 50-1000 VAC. This would typically be used in most commercial and residential electrical systems and equipment. A medium voltage distribution system will range from 1000-4160 VAC. This will be used to in Industrial electrical power applications such as manufacturing plants. A high voltage transmission system will range from 4161 VAC and up. This is used to transmit the electrical voltage from the generation points that provide electrical power to the electrical grid.

Alternating current electrical systems can be monitored by an EPMS system through proper selection of metering devices and the locations within the system that these meters are installed to determine power quality, power consumption, power usage and costs and power usage efficiency. Electricity is a force that usually cannot be seen with the naked eye. An EPMS system with metering in the correct locations will allow the end user to see what can’t be seen with extreme accuracy and allow any facility to operate with the ability to foresee and reduce unplanned down time to electrical equipment when needed for operations.

A transformer is a static machine used for transforming power from one circuit to another without changing frequency. With an alternating current, a transformer will wither raise or lower the voltage. As an example the transformer will change the voltage from 12kv to 480v, or from 480v to 208v. Typically we will see a three phase transformer has Star (Wye) and Delta configurations and has three sets of primary and secondary windings. Transformers are critical pieces of equipment in any electrical system as they are used to create an electrical voltage that is useable by the customer’s equipment per industry standards.

Basic transformer types are “Dry” and “Oil filled” transformers. A dry transformer is cooled by air only. Oil filled can be cooled in several ways. ONAN are “Oil Natural Air Natural”, ONAF are “Oil Natural Air Forced”, and OFAF are “Oil Forced Air Forced”.

The EPMS system would be able to monitor the transformers switch positions, transformer temperature (Hi, Low), transformer pressure (Hi, Low) etc. This type of device is usually monitored though a sequence event recorder (SER) with digital inputs.

The EPMS system is a Web Based Monitoring system that monitors all specified locations in the distribution system. The EPMS is may include, but not to be limited to, remote devices for monitoring, control and protection, device communication interface hardware, intercommunication wiring, monitoring stations, software, software configuration, ancillary equipment, startup and training services.