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Demand Control
１．１．１．１． Overview
２．２．２．２． Examples of Electricity Billing System
３． Explain of Demand System
４． Demand Monitoring System
Confidential
CONTENTS
BackgroundBackground
１．Overview
In Japan, the energy saving became most important by the Great East
Japan Earthquake.
The sales of the demand power monitor device increased rapidly.
In future, we think that the demand for this device will increase equally
in the overseas market where power supply becomes more difficult.
Electricity billing System and PurposeElectricity billing System and Purpose
１．Overview
The electric bill of a factory and the building is the total of a rate of the
consumption electricity (kWh) and the rate of the max. mean electricity (kW).
In the case of Japan, the mean electricity is the mean of 30 minutes.
The rate of the max. mean electricity is a measure to promote equalization
of the energy consumption.
It is the same purpose that the daytime electric rate is set higher than the
nighttime.
The demand monitor deviceThe demand monitor device
The demand monitor device calculates the present and future mean
electricity.
When the future mean electricity is more than the target value, the
device issues the alarms.
Electric bill = Energy consumption (kWh) × rate + Max. Mean electricity (kW) ×rate
Demand (power)= Mean electricity (power consumption)
Electricity billing System in Japan
NOTE: The timetable is different every electric power company.
Rate of charge
Demand Power
of Demand
Charge
Total Charge＝Basic Charge＋ｋWh Charge
Basic Charge=Demand Charge × Power Factor Discount rate
Power Factor Discount rate：1－（Power Factor－0.85）→Maximum 15% discount
The way of
Calculation
DetailItem
2． Examples of Electricity Billing System
Holiday
Weekdays
Y yen/kWhX yen/kW
Y yen/kWhZ yen/kWhY yen/kWh
Q yen/kW
More than
500kW
R yen/kW
08.30～18.30
kWh Charge
21.30～08.30
Demand Charge
Less than 500kW
18.30～21.30
The maximum of the past 12 monthsLess than 500kW
To contract with the electric power company based on the results.More than 500kW
Electricity billing System in Thailand
Total Charge＝Demand Charge＋ｋWh ChargeTOD
Total Charge＝Demand Charge ＋ ｋWh Charge + Service ChargeTOU
SystemType
Z THB/kWh0Y THB/kWX THB/kW
Off21.30～08.30
Partial08.30～18.30
Peak18.30～21.30
kWh Charge
Demand Charge
kWh Charge
X THB/kW
Demand Charge
Z THB/Month
Z THB/unit0
Off22.00～09.00
Saturday, Sunday, Holiday
Y THB/kW
Peak09.00～22.00Monday ～
Friday
Service Charge
2． Examples of Electricity Billing System
Demand system A(Japan, Taiwan, Thailand etc.)
t
kWh
1 month
kWh1
kWh2
kWh3
kWh4 kWhn
Demand = kWh of T term×60min.／Tmin.
Demand max. = Max.( Demand1…..n) 15minTaiwan
30min.Japan
3． Explain of Demand System
Demand system B(China etc.)
Demand = kWh of T term×60min.／Tmin.
Demand max. = Max.( Demand1…..n) 1minΔT
15min.T
TTΔT
ｔ
kWh
kWh1kWh2
3． Explain of Demand System
4． Demand Monitoring System
6600V
Energy Meter(Electric power company)
Pulse
Demand monitor device(Mitsubishi Electric)
Alarm output
Demand system A Monitoring System (in Japan)
It is important to match the clock of
the demand monitor device with the
clock of the energy meter.
Demand
Monitoring
andControl
4． Demand Monitoring System
Demand monitor device(Mitsubishi Electric)
Alarm output
Demand system A Monitoring System (in Japan)
When the calculated demand
exceeds the target demand,
this device produces alarm
outputs.
Present Demand Calculated demand
Target demand
Present time
This device measures the present
demand. And this device
calculates demand arriving at the
end of the interval for 30 minutes.
4． Demand Monitoring System
High Voltage
Circuit
Energy Meter(Electric power company)
Demand system B Monitoring System
PC
or
PLC
ModBusI/F
Demand
Monitoring
and
Control
Research Items
5． Research Items
What is used for demand control?
Requirements to the demand
monitoring device
System constitution Refer to 4.Demand monitoring
SystemDemand
Monitoring
System
1month, 12monthes or OtherMaximum term of switching
Demand
System
Weekend and Holiday
discount System
Examples
a. Triple tariffs（Three counters)
b. Pass word function
c. Clock function etc.
Power Factor discount system
Nighttime discount System
A, B or OtherRefer to 3.Explain of demand System
Type
Refer to 2.Examples of
Electricity Billing SystemThe way of CalculationBilling
System
NoteItem
