Technical ReportPDF Available

Telemetric System Of Intermediate Pumping Stations Control

Authors:

Abstract

Telemetric System of Intermediate Pumping Stations Control is designed for remote monitoring and control of unmanned intermediate pumping stations working on main lines in Lodz (Poland) agglomeration heating system, from central dispatching room. The intermediate pumping stations are located in the range of 4-6 km from the central dispatching room. Their task is to maintain proper pressure distribution in previously chosen points of the heating net. The task is fulfilled by adaptive control of efficiency and selection of the number of working pumps. Basic system functions are as follows: - automatic pumping station start - automatic planned and emergency pumping station shut down - automatic pressure control – the selection of the number of pomps and efficiency of each pump - automatic and planned to turn on of backup main supply - protection of pumping station buildings against burglary or fire - leakage detection in sets of pump units and monitoring of building flooding - fittings control for main line protection in case of any pumping station emergency shutdown - emergency shutdown of pump units in case of increased vibrations or temperature - providing redundant radio-communication with the central dispatching room - ensuring of an alternative remote control - local and distant monitoring of pumping station work (of hydraulic and electric systems) - recording of all-important occurrences and changes of selected work parameters
doc: R-050701E03_SOC_advert/Ver:9 1 Lodz, April 2005
TELEMETRIC SYSTEM OF INTERMEDIATE PUMPING STATIONS
CONTROL (STSP)
Telemetric System of Intermediate Pumping Stations Control (STSP) is designed for remote monitoring and controlling of
unmanned intermediate pumping stations working on main lines in Lodz heating system, from central dispatching room. The
intermediate pumping stations are located in the range of 4-6 km from the central dispatching room. Their task is to maintain
proper pressure distribution in previously chosen points of the heating net. The task is fulfilled by adaptive control of
efficiency and selection of the number of working pumps.
Basic system functions are as follows:
automatic pumping station start;
automatic planned and emergency pumping station shutdown;
automatic pressure control selection of the number and efficiency of pumps;
automatic and planned turning on of backup main supply;
protection of buildings against burglary or fire;
leakage detection in sets of pump units and monitoring of building flooding;
fittings control for main line protection in case of any pumping station emergency shutdown;
emergency shutdown of pump units in case of increased vibrations or temperature;
providing of redundant radio-communication with the central dispatching room;
ensuring of an alternative remote control;
local and distant monitoring of pumping station work (of hydraulic and electric systems);
recording of all-important occurrences and changes of selected work parameters.
For their strategic importance to the city
heating system, the pumping stations should be
reliable and their smooth running should be
controlled permanently. Realization of this
requirement is possible only when the reliability
of the communication system is also up to these
requirements.
A radio system with an additional backup
communication channel was selected as a
solution, which met the mentioned requirements
best. Two paths of data transmission were used,
i.e.: main and redundant paths radiomodems
operating on licensed frequency in 400MHz
band.
The figure shows the structure of Telemetric
System of Intermediate Pumping Stations
Control (STSP).
Following elements are exposed:
central dispatching room for Heating Net-
work Plant (ZSC);
intermediate pumping stations (SOC_D,
SOC_P).
Specialized radiomodems MDS 4710 were
applied to communication lines.
doc: R-050701E03_SOC_advert/Ver:9 2 Lodz, April 2005
The system includes two data concentrator stations (KD) located in the intermediate pumping stations and the central point
of data acquisition base station (SB) enabling communication with pumping stations
Stations by means of two additional operator stations SCADA (SO).
OPERATOR STATIONS
Tasks of an operator station (SO) are:
1. Visualization of acquired data describing the present state of technological process
2. Remote manual or parametric automatic control of the object
3. Data archiving.
Operator stations are located in the central dispatching room and they enable remote control of the pumping station in one of
the following modes:
emergency manual (OPERATOR MODE) in
case of emergency situation or repair and
maintenance work;
parametric (AUTOMATIC MODE) enables
setting of selected parameters for the autonomic
system of local automatic regulation.
Operator stations (SO) read independently actual
data from the base station (SB). Data are read by
means of a serial interface. Because commonly used
standards are utilized, connection of the base stations
(SB) to any visualization and control systems is
possible.
BASE STATION
As it has been mentioned, the base station (SB) is
responsible for reading data from data concentrators
(KD) using one of available communication
channels. An adaptable configuration of the base
station and data concentrators allows future
development of the system. The figure shows the configuration where intermediate pumping stations are equipped with a
digital radio link working on licensed frequency (main and redundant links). Both paths use radiomodems MDS 4710E.
Base station (SB) enables connecting additional data concentrators and other monitoring and controlling units to the system,
as for example DGH intelligent modules, SAIA PLC controllers etc. Adding more concentrators is realized by software
reconfiguration in the base station. Base stations (SB) are equipped with 8 channels for serial data transmission. Two channels
are used to communicate with SO station (operator) and 2 for transmitting data to data concentrators.
DATA CONCENTRATORS
Their task is to ensure reliable data transmission with redundancy. Independent transmission paths increase the reliability in
case of maintenance works or malfunction of one of them. Any data concentrator acquires data from primary controller and
controllers of local units connected to the network and transmits them to the base station (SB) through one of the
communication paths. Transmitted data are protected against accidental interference; data flow is monitored and data are
retransmitted in case of error detection.
Software for controllers does not contain any dedicated elements connected with communication i.e. the built-in operating
system is harnessed to the maximum degree.
Smooth running of the telemetry and controlling systems is independent of mains continuous work, which is ensured by
using uninterruptible power supply (UPS).
doc: R-050701E03_SOC_advert/Ver:9 3 Lodz, April 2005
PRIMARY CONTROLLERS
Primary controllers (SP) perform most control and regulation functions. Local controllers connected to a common bus
perform remaining functions. Controllers are connected with one another with RS485 interface. To encourage redundancy,
important signals meaning malfunction are sent through independent additional signal lines.
Any primary controller is responsible for the performance of the following functions:
automatic control of all working devices of the pumping station hydraulic system;
control and monitoring of pumping station power supply, including the control of automatic start of stand-by power
supply;
control and monitoring of the access control system, fire protection system and flooding control system;
monitoring of the access to remote control functions.
Primary controllers and local controllers are designed so as to be capable of performing all autonomic functions without the
necessity of communicating with dispatching room stations.
LOCAL CONTROLLERS
Function of monitoring of the smooth run of pump units is partly performed by programmable local controllers adjacent to
these units and partly by the primary controller (a diagram below).
The tasks of these controllers are:
performing of algorithms of units correct work monitoring;
local measuring of selected parameters;
adjustment of selected parame-
ters;
detection of possible leakage in
pump units.
They are responsible for
measuring signals from sensors of
vibration, temperature, dampers
positioning, signal filtering and for
comparing of the measured values
with the maximum ones. There is
one local controller installed for each
pump unit.
The primary controller cyclically
reads monitored parameters by the
serial interface and it shuts down the
unit if set limit values are overshot.
As an additional protection,
independent binary signals come into
the master primary controller (SPM),
informing about overshooting of
limit vibration and temperature
values in individual units and forcing
an immediate shutdown of the unit.
This way the system reliability is
increased in case of communication
loss with a given controller.
Communication between primary
and local controllers is performed by
means of a serial interface. Because
of the RS485 standard in which the
doc: R-050701E03_SOC_advert/Ver:9 4 Lodz, April 2005
local controllers work, an RS485/RS232 converter is used, which enables connecting to the primary controller.
To ensure a proper redundancy level, two additional binary signals are provided independently from each controller (SP) to
the master primary controller (SPM). They signalize:
1. The state of overshooting maximum temperature of unit bearings
2. The state of overshooting permissible value of vibration level.
Appearing of one of these signals runs emergency pump shutdown algorithm independently of correct work of the
transmission cable.
Engine bearings are equipped with temperature sensors PT100 and piezoelectric vibration sensors. Specialized amplifiers
converting low-voltage signals to current signals were placed in measurement lines to properly form the converter
performance.
To ensure possibility of unmanned operation of intermediate pumping stations it was necessary to create a system, which
automatically detects planned and accidental leakage of water in the network. During normal work of pump units, small
quantities of water from bearings cooling system and pump natural leakage are drained to waste water sumps nearby.
Periodically, during normal operation, much larger quantities of water are drained to the sumps, e.g. water from venting system
or bearings cooling installation. Therefore, some modifications in the design of waste water sumps were made and float
sensors installed. Software of local controllers are adjusted to system properties and they react only when water getting out of
the cooling system of bearings or any other large leakage which causes float sensor working lasts longer than 5 minutes. It
allowed monitoring leakages and reacting only when there is a real danger to the intermediate pumping station.
As well, water-flooding sensors connected to anti-breaking system were installed in pipeline passages.
RADIO CONNECTION ON A LICENSED FREQUENCY
In this line, the communication device a radiomodem - is connected to the computer using RS232 serial interface and it
transmits serial data to a distant data processing system by means of radio waves in 400MHz band. There is employed a “star”
configuration here, in which the central station works with an omnidirectional antenna and communicates with distant stations
(SOC_D and SOC_P) sequentially on one frequency. Distant stations are equipped with directional antennas in order to
increase their range and decrease the effect of disturbances and interference from other transmitting devices.
Such a system works on a leased frequency. Frequency was assigned basing on an application with project documentation
of the radio network development, which included the network description, objectives and propagation and disturbance
analyses.
www.commsvr.com
www.cas.eu
commserver@cas.eu
ResearchGate has not been able to resolve any citations for this publication.
ResearchGate has not been able to resolve any references for this publication.