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Functions
3.3 Demand Measurement
SICAM P38 P39, 3-phase Power Meter with Multi-Tariff function, User Manual
E50417-H8940-C564-
4
, Release Date
06.2018
16
3.3
Demand Measurement
1. Terms and Definitions
Demand means average power within specified period. The maximum value of demand recorded within
specified period is maximum demand.
Current demand means average current within specified period. The maximum current value recorded within
specified period is called maximum current demand.
Demand cycle means continuous equal intervals for measuring average power.
Sliding window time means time interval for measuring maximum demand through recursion. It is less than
demand interval.
Temporary unit means the memory unit of the meter, used for temporary storage of power value or current
value when calculating maximum demand.
Demand interval can be selected from 5, 10, 15, 30 and 60 min. Sliding window time can be selected from
1, 2, 3 and 5 min. Demand interval is five times the sliding window time and is 60 at maximum.
2. In the event of power-on, zero clearing, clock adjustment and interval change of voltage line, the meter will
execute demand measurement depending on demand interval from current moment. When the first demand
interval is completed, maximum demand will be recorded at slip interval. Maximum demand will not be re-
corded within an incomplete demand interval.
3. When power direction changes, temporary demand unit will be cleared. Temporary demand unit will not be
cleared when across rate period to ensure continuity of maximum demand measurement. Zero clearing of
temporary unit is necessary when:
• Overall clearing of meter;
• Clearing maximum demand upon communication command;
• Clearing maximum demand manually through button;
• Change of power direction;
• Settlement among different months.
4. This meter is capable of various maximum demand calculation functions, including import/export active
demand and occurrence time, combined reactive and four-quadrant reactive maximum demand and occur-
rence time, import/export apparent demand, maximum current demand of Phase A, Phase B and Phase C
and occurrence time.
5. Combined reactive maximum demand means the quadrant with maximum demand value among reactive
quadrant participating in combined computation. For example, value of reactive combined status character
2 is 05 H. Typical combined reactive 1 = 1
st
quadrant re 2
nd
quadrant reactive. Assuming reactive
maximum demand of 1
st
quadrant in a demand interval is 100kvar and the same of 2
nd
quadrant is 200 kvar,
maximum demand value of combined reactive demand 1 within the same demand interval will be 200 kvar.
6. This meter is provided with two types of zero clearing for demand: clearing via communication and manual
clearing with button. For description of the latter, see subsequent content.
7. For time generating maximum demand, minute synchronization or clock synchronization is available. This is
controlled by parameter mode character 2. For mode character 2, see the table below. Such mode supports
parameter setting and alteration through communication.
Bit
Function
Bit Value vs Function
Default
Bit 7
Reserved
0
Bit 6
Reserved
0
Bit 5
Demand synchronization mode
1: minute synchronization 0: clock syn-
chronization
1
Bit 4
Extreme value settlement
1: daily 0: monthly
0
Bit 3
Reserved
0
Bit 2
Reserved
0