Real-Time Remote Monitoring of a Distribution System

1
Real-Time Remote Monitoring of a Distribution
System A Case Study in Washington D.C.

• Srinivas Panguluri (Shaw Environmental, Inc.),
• Robert M. Clark (Consultant), and
• Roy C. Haught (U.S. EPA - Water Supply and Water
  Resources Division)
• Presented by
• Srinivas Panguluri, P.E.

2
Presentation Outline

• Overview of the Case Study
• System Selection and Implementation
• Lessons Learned
• Technology Trends Review
• QA - Discussion

3
Overview of the Case Study

• In 1996, following a number of Colifom violations
  EPA Region-3 directed DC Water and Sewer
  Authority (WASA) to implement several corrective
  actions
• One of the corrective actions proposed was remote
  monitoring of water quality. In 1997, EPA
  initiated a study to install a remote monitoring
  network

4
Overview of the Case Study

• Fort Reno Tank was selected as the first location
  for remote monitoring system implementation
• Four water quality parameters were selected for
  monitoring in this Case Study - Temperature,
  Chlorine, Turbidity, pH
• The study was later on expanded to two other
  locations Bryant Street and Blue Plains
• The existing WASAs SCADA system was adapted for
  data collection

5
Overview - System Layout
6
Overview Publishing Data
7
Overview Web Access
8
Overview Data Browsing
9
Overview Sampling System
10
Overview Sample Data
11
System Selection and Implementation

• Off-the-shelf online monitoring instrumentation
  for Temperature, Chlorine, Turbidity and pH with
  4-20 mA external outputs were used
• A custom water sampling system was built for each
  site
• A Preliminary Assessment for selecting and
  implementing the appropriate Data Acquisition
  System was performed. Key factors are outlined as
  follows
• Initial and ongoing - EPA/WASA

12
System Selection and Implementation

• Ease of use and programmability - Proprietary
• Hardware Networkable - Yes
• System Scalable - Yes
• Data/System Redundancy - Yes
• System Security One Way Data Transfer
• Remote Access Capability - Not Available
• System Response Time - More than adequate
• Historical Trend Data Storage/Transfer Capability
  - Limited Storage
• Availability of Local Support - WASA

13
System Selection and Implementation

• Software Features Graphics, Trending and
  Reports
• Remote Access - Added a Windows-based PC
  workstation to dial into using pcAnywhere/
  Reachout Software (added security, prevents
  remote access to the WASA SCADA system)
• Trending - Export Program in Access97
• Reporting - Queries to chart in Excel97
• Power Availability - Yes

14
System Selection and Implementation

• Summary
• Existing Scalable SCADA System and onsite support
• Programs were developed to work around some of
  the existing system limitations
• Phased Implementation

15
Lessons Learned

• Train and retrain hands-on as much as possible
  both for operation and troubleshooting activities
• Teach operational awareness
• Need to customize the users manual, provide
  phone support

16
Lessons Learned

• Frequent changes in WASA support personnel
  affected some troubleshooting activities
• Dead pigeons were found floating in the Fort Reno
  tank by WASA personnel. The cleaning procedure
  damaged some of the sensor equipment.
• The initial data could not be validated due to
  the lack of calibration records

17
Lessons Learned

• The network link between the water and sewer side
  has limited bandwidth. The errors generated in
  the network traffic using this link frequently
  cause a bottleneck in the system and eventually
  led to a few system crashes
• Lack of communication between WASA personnel and
  the contractors working at the Fort Reno site
  caused the tank to overflow and the sampling
  system was submerged

18
Technology Trends Review

• Instrumentation
• Conventional Ion selective electrodes, GC, LC,
  optical, etc.
• Bio-sentinels based on observing and evaluating
  the behavior of living organisms - Daphina, Fish,
  Clam, Bacteria, Algae, etc.
• Bio-sensors - DNA based, flow cytometry, etc.

19
Technology Trends Review

• Instrumentation (Contd.)
• Solid State Microchips
• Other (ZAPS)
• Remote Data Acquisition Technologies
• Wireless Cellular, CDPD, Cellmetry/Aeris,
  Radios ISM/VHF/UHF, PCS, Satellite
• Encryption - Key Based DES/AES symmetric (or
  secret-key), RSA asymmetric (or public-key)
  algorithms

20
Technology Trends Review

• Remote Data Acquisition Technologies (Contd.)
• The Polled System
• Pros Data gathering is simple, no collisions,
  link failure can easily be detected
• Cons Interrupt type request cannot be handled
  immediately, wait time increases with the number
  of locations, all communications must pass
  through the master.

21
Technology Trends Review

• Remote Data Acquisition Technologies (Contd.)
• The Interrupt System
• Pros Reduces unnecessary transfer of data,
  quick detection of urgent status information,
  allows peer-to-peer communication
• Cons Link failure may be detected after a long
  period of time, operator action is needed to have
  the latest value, collision of data may occur and
  cause delays

22
Technology Trends Review

• Power Requirements
• Solar and other power options for instruments and
  data acquisition equipment
• Evaluation of Technologies
• USEPAs TE Facility, Cincinnati, OH
• The New WATERS Center
• Field Locations (large and small systems)

23
Q A - Discussion

• What is the intended use of real-time
  monitoring data?
• a. Network model calibration,
• b. Early warning system, or
• c. Both

24
Q A - Discussion

• What parameters should be monitored, selection
  criteria for monitoring instrumentation?
• a. Conventional (Physio-chemical) - pH, ORP, DO,
  Turbidity, etc.
• b. Biological Daphnia, fish, clam, other
• Both

25
Q A - Discussion

• 3. How to select and implement/integrate the
  various SCADA system components for data
  collection?
• a. Implement new or integrate with existing SCADA
  system
• b. Communication media Cable/wire, cellular,
  satellite, RF, etc.
• c. Data collection and handling

26
Q A - Discussion

• 4. Intended use and interpretation of real-time
  data?
• a. What do the numbers mean?
• b. Do we need data filters?
• How do we verify and report the data?
• 5. Monitoring system maintenance and management?
• a. Proper training/retention of people
• b. Instrument calibration and recordkeeping
• c. Commitment from management xxx,xxxs

27
Acknowledgements

• U.S. EPA Support
• WASA Support
• Shaw Environmental, Inc.