Power utilities around the world are rolling out smart meters in order to enable automated meter reading and optimized energy management. The X2 capacitors from the EPCOS B3293* heavy duty series of film capacitors are well suited for these meters because they operate reliably over a long service life under extreme environmental conditions.
Smart meters are continuing to enjoy strong growth rates as more and more power utilities implement automated meter reading (AMR) to save the expense of periodic trips to each physical location to read a meter. Moreover, information based on near real-time consumption can help both utilities and their customers better control the use and production of energy.
An estimated 40 percent of all power meters are installed outdoors, where they are exposed to high humidity, as well as extreme and rapidly changing temperatures. While outdoor mounting poses no serious problem for conventional meters with relatively simple electromechanical designs, the challenge is much greater for electronic smart meters. Smart meters typically employ a capacitive power supply where the key component, the AC capacitor, is permanently connected in series to the power line. This, combined with high humidity and temperatures, can significantly reduce the capacitanceThat property of a system of conductors and dielectrics which permits the storage of electricity when potential difference exists between the conductors. Its value is expressed as the ratio of a quantity of electricity to a potential difference. A capacitance value is always positive. of conventional capacitors and thus severely limit their useful life in smart meters.
Historically, standard EMI suppression capacitors have been selected for this particular circuit position because of their safetyClass X capacitors are used in "across-the-line" applications where their failure would not lead to electric shock. Class X safety caps are used between the "live" wires carrying the incoming AC current. In this position, a capacitor failure should not cause any electrical shock hazards, rather, a capacitor failure "between-the-lines" would usually cause a fuse or circuit breaker to open. approval (UL, ENEC). These capacitors, however, are not designed specifically to satisfy the long-term operation requirements of the power meter.
