A practical approach to wireless Power by lcy20702


									 A practical approach to wireless Power
  A practical approach to wireless Power
 Quality, Energy and Facilities Monitoring
 Quality, Energy and Facilities Monitoring
             P.K. Lee 1 and L.L. Lai FIEEE 2
                      1                    2

1 Powerpeg NSI Limited, Hong Kong
2 Energy Systems Group, City University, London,
United Kingdom
• In this paper, the authors discuss the way to adopt the
  cost effective SMS applications to Power Quality, Energy
  and Facilities Monitoring System. Also, the limited up to
  160 characters will be considered during the design
  which cannot be used on high data volume such as
  waveform pattern is not preferred but simple message
  such as voltage dip % is good enough.
System Diagram
• Short Message Service (SMS)
• the SMS is very cost effective transmission media in
  which real-time connection between point-to-point or
  point-to-multipoint are not required.
• GPRS, 3G or 3.5G network are available, it is more
  convenient for higher speed data transmission services,
  consumer can enjoy advanced, feature-rich data
  services such as color Internet browsing, e-mail on the
  move, etc. However, SMS is still very popular since it can
  be used for pushing method without on-line connection
  and the cost is acceptable in some applications.
         Characteristic of SMS
• SMS may be one of the
  simple, quick and cost-
  effective strategy when
  on-line connection is not
  needed for remote area
  and pushing method is
  preferable such as energy
  profile collection and
  alarm reporting, voltage
  dip % etc.

• Operating Cost
  the reason for the adoption of SMS is the cost. The SMS
  offer a very competitive price in many countries already.
  Some of them, the SMS are even free of charge if they
  are sent or received from the same mobile services
• Connection/Connectionless:
  SMS is a connectionless media. It pushes the SMS to
  single/multi users or receivers without any point-to-point
  or point-to-multipoint on-line connection
  - no feedback or acknowledge
                       Data Volume

• It has limit with typically 160 characters
• good enough in many cases such as voltage dip
  %/fault/trip alarm reporting in building services facilities.
  Energy or water flow date collections from properties
  management or voltage Dip level from fault recorder in
  Power Utilities, etc are some typical examples.
• waveform in power system is not recommended since it
  needs a large volume.
             Data Transmission:
• Character length per message is recommended to be
• Transmitted message into few messages when they are
  over the preset limit
• Encryption, Decryption, handshaking, missing data,
  CRC and priority may need is they are sensitive
  message or critical data.
• Advanced Encryption
  Standard AES is one
  of the most popular
  encryption standards
  that is acceptable to
  many Power Utilities
  already and can be
  adopted to SMS or
  GPRS as well.
          Data compression
• The main purpose for this feature is for
  cost saving.
• It should be done from the modem’s
  firmware before transmission and after
• Optional selection only
              System Scale
• the system design for
  10 remote sites are
  different from 100 or
  500 remote sites.
• Multiple com ports or
  SMS gateway from
  the sms server may
  be necessary when a
  large system is
    Intelligent firmware inside the modem

• An intelligent firmware can be designed and downloaded
  into the GSM modem
• Example : MODBUS Master firmware inside the modem
  is able to map the register points inside the PLC or
  energy meters or any device with MODBUS RTU
  protocol via RS232 or RS485. You need to design a
  graphical User Interface (GUI) to download the firmware.
• Set points can be defined to monitor those register points
  for monitoring and controls.
• Data dump with interval setting can be defined to collect
  data from energy meters and push to the SMS Server
  Software periodically after encryption and compression.
• Report to the mobile phone of maintenance staff directly
  with readable messages
        Graphical User Interface (GUI) example
General Setting    Data Records Contact list and contact group
                     GUI example

• General Setting : to define the communication of the
  modem speed and some basic setting during the
  operation of the modem
• Data Records : to define what registers should be
  monitored and what set points to trigger the alarm
• Contact list and group : to define who will receive this
  message during alarm and which group he belongs to.
  Eg. Group A has 3 people from contact list,
     Group B has 1 people from contact list.
SMS Server Software design consideration

 –   Graphical User Interface (GUI)
 –   Database structure.
 –   Communication structure.
 –   Data logging such as analogue log.
 –   Graphical plot.
 –   Reporting format.
 –   Sequence of Event (SOE).
 –   Human Machine Interface (HMI).
 –   Diagnostic
 –   Protocol
                                                                  Adhoc/ Reset to send comma
                                                                      to modem for data dump
                                           Modem COM port configuration
 Status information

Global Event Log      Analogue Input (AI) Log
                                     Change of Status (COS) Log

                                                     Alarm Log
Thank you!

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