Key-pad Prepayment Energy Meter is a type of meter that exchanges information through virtual carrier – token.
Token is a serial of numbers, for example 2837 5872 3731 6854 3423. An exclusive token can be created by prepayment system, and user just need to enter the token to meter with key-pad. Meter will decode the token according to agreement so that the recharge/purchase can be achieved.
Since meters that comply with IEC62055 need to pass the tests of STS and adopt standard safety module encryption calculation, the meters and systems from different manufactures are always compatible with each other.
IEC62055 standard covers prepayment system, CIS users info system, energy selling system, transmission carrier, standard of data transmission, prepayment energy meter and interface standard etc. It is an architecture about the entire prepayment system.
A.Content of IEC62055
IEC62055－21 Framework for standardization
IEC62055－31 Static payment meters for active energy (classes 1 and 2)
IEC62055－41 Standard transfer specification (STS) – Application layer protocol forone-way token carrier systems
IEC62055－51 Standard transfer specification (STS) –-Physical layer protocol for one-way numeric and magnetic card token carriers
IEC62055－52 Standard transfer specification (STS) –-Physical layer protocol for a two-way virtual token carrier for direct local
connection
B.About STS association
1.IEC62055 standard is developed and maintained by IEC TC13 WG15 who are maintained mainly by STS association.
2.STS is developed and published by ESKOM – South Africa national electric power cooperation in 1993.
3.Founded in 1997, STS is dedicated to following tasks: prepayment energy meter technique standard setting, standard system maintenance, and improving technique to meet international requirement. STS association ensures compatibility among different products and systems by managing members’ cipher codes, manufactory numbers, meter’s serial numbers and laboratory tests.
C.STS organization
STS（Standard Transfer Standard）has become the world’s only standard for open prepayment system. To apply to this technology users need to get STS authorization so that the security can be guaranteed. STS has been adopted firstly by South Africa and now many developed and developing countries. Presently there are at least 20 million STS meters installed in more than 40 countries and 500 electricity companies.
D.STS features
Exchanging data and information through virtual carrier (20 digitsu token), STS prepayment system goes well with development of communication technology in future.
STS standard can be used to define and recharge creditu for energy meters, water meters, gas meters and meters for other public usages.
STS is a secured communication system in which information passesu between energy selling site and meter.
Taking IEC 62055-41 as the onlyu international standard for prepayment system, STS is a security transmission standard which opens to the world.
Cipher code security technique isu furnished (Cipher codes are classified. Electricity companies manage cipher codes of their own)
Every TOKEN, meter, energy selling site and the entireu prepayment system enjoys protection from different level of security.
Reliable encryption system technically reduces attacks to theu system.
Multi-system ensures update in time.u
Products involved in theu system need to get approval from STS.
TOKEN is reliable in transmission.u Meter accepts every TOKEN only once, repeat entry will be ignored. Every TOKEN is combined with the meter’s information and works on nominated meter only.
There are at least 20 million STS meters installed in hundreds ofu electricity companies in the world.
STS ensures compatibility amongu different meter products from different manufactures: electricity company can purchase meter or prepayment system from any manufacture that has passed STS approval without worrying about system security.
E.Features of Key-pad energy meters
Virtual carrier - 20 digits tokenu
Supports TOUu (time-of -use) pricing and staged pricing
STS approvedu
Multiple alarmsu (meter alarm, short message and email) for balance
Overload breaking/ loadu control
Emergency overdraft and friendly breaking modeu
Anti over creditu function
Built-in RS485 or PLC communication module to support long-distanceu recharge.
Supports keyboard entry and infrared entry in case of failure ofu long-distance recharge.
Meter to be installed in meter case, so as tou prevent touching.
Built-in relay. Supports detection and alarm for relayu problem.
Anti-tamper functionu
Supports browsing of consumptionu history.
Helps to achieve separated type design.u
F.STS network prepayment system
Combines AMR system with prepayment managementv system.
Adopts IEC advanced technology to archive prepayment rechargev through virtual carrier. Multi-ways recharge goes well with development of technology in future.
Encrypted recharging code can be transmitted throughv IC card, TOKEN, infrared and radiocast.
With help of internet, meterv prepayment recharge can be as easy as mobile phone recharge. Long-distance recharge and local assistance both ensure success of recharge.
Users do notv have to bother with IC cards, magnetic cards or other complicated cards.
System security is approved and guaranteed by IECv
Automaticv report for abnormal situation. Reports are easy to check.
Short messagev alarm and email alarm when short of credit.
Automatic long-distance updatev for TOU pricing and staged pricing.
Achieves prepayment, users datav collection, TOU pricing and staged pricing.
G.Multi-ways of recharge
Recharge through short message (SMS)v
Recharge throughv internet
Recharge in operation hallv
Scratch cardv
POS recharge inv stores
Recharge cardsv
Recharge though online-bankv
Recharge thoughv service hot line (i.e. 95598)
Recharge through ATMv
H.Caution:
Prepayment energy meters that don’t have STS approval are not ensured with security. It’s risky for users if the calculation is controlled by manufactory only. Without tests and approval, meters and energy selling system can not work in the same system with meters from other manufactories. In this situation energy supplier has to run the risk of relying on the manufactory only.
I.World’s major manufactories for Keypad prepayment energy meter
Conlog, Landis&Gyr, Actaris, Inhemeter, etc.