Technical data

36 Electricity meters | 2CMC480022C0003
DELTAmax
Specialfeatures-RTC,PV,LP,MD,logandTHD
DELTAmax has an internal clock that handles a number of
time dependent functions such as load profile, maximum
demand, previous values, event and quality log, time con-
trolled outputs and tariffs. The data from these functions
are only readable via serial communication. When all av-
ailable memory for a time dependent function is used, the
oldest data record for that function will be over-written.
Changing interval length or number of values to stored in
a function will reset all values stored.
Internal clock
The internal clock, sometimes called real time clock or RTC, has
a built-in calendar and keeps automatically track of leap year and
daylight savings time (DST). The DST function is optional.
Backup of the clock during a power failure is provided by a super-
capacitor. The time is controlled from a quartz crystal based clock..
Time and date is set via push buttons or via communication.
The internal clock is approved according to IEC 62052-21 and
IEC 62054-21. These standards specify the requirements for time
switches in electricity meter related products. The accuracy is
better than 5 ppm at room temperature.
Previous values
The previous value feature will store all energy registers and input
counter values together with a date/time stamp upon change of
day or month. All total values are stored and in meters equipped
with the tariff feature all the tariff registers will also be stored.
Load Profile
The load profile stores the energy consumption at pre-defined
intervals. The interval lengths are 15, 30 or 60 minutes. The default
value is 60 minutes.
The quantities that can be stored for each interval are active and
reactive energy, both imported and exported energy, and the
number of pulses registered on input 1 and 2. Storage of reactive
energy is only possible on meters measuring combined energy
and storing of pulses requires that the meter is equipped with the
corresponding number of inputs.
The load profile function uses the standard time setting irrespective
if the daylight savings time function is activated or not.
Maximum Demand
In the maximum demand function, the mean power in each interval
is measured and the maximum mean values are stored together
with a date/time stamp. The interval lengths are 15, 30 or 60 mi-
nutes. The default value is 15 minutes.
For each set of maximum demand values the end date/time of
the period is stored.
The quantities that can be stored for each interval are active and
reactive energy (imported energy only), and the number of pulses
registered on input 1 and 2. Storage of reactive energy is only
possible on meters measuring combined energy and storing of
pulses requires that the meter is equipped with the corresponding
number of inputs. In tariff meters, the maximum demand is stored
for each tariff.
Event log
The event log function logs the following events:
• Overvoltageoneachphase(+6%)
• Undervoltagelevel1oneachphase(-10%)
• Undervoltagelevel2oneachphase(-15%)
• Phasevoltageoutage(-15%)
• Negativepower
• Totalpoweroutage
• Presenceofcurrentharmonics
For the over- and undervoltage events a percentage level with
respect to a nominal voltage is given which is programmable. The
phase voltage outage level use the same level as undervoltage
level 2. The negative power event will be logged if abnormal
negative power is detected.
For current harmonics a percentage level for the total harmonic
distorsion of the harmonics measured can be set and the event
will be logged if that limit is exceeded.
THD
The current harmonics (2-9) together with the fundamental is
measured sequentially one at a time (approximately 1 harmonic
each second). The total current harmonic distortion of the harmo-
nics measured is displayed in percent. The separate harmonic
frequencies measured are multiples of the fundamental frequency
(normally around50or 60 Hz)upto the 9th harmonic butnot
higherthan500Hz.At60Hzforexamplethe9thharmonicwill
havefrequency540Hzandwillthennotbemeasured.
THDdataisdisplayedontheLCD.THDdataanddataforindividual
harmonics can be read out via serial communication.