Netalyser is a suite of advanced, high-fidelity simulation tools that we have developed for the dynamic analysis of power generation and process plant utility systems. It has been designed for the simulation of the transient behaviour of complex steam, gas and hydraulic networks and their associated peripheral systems such as steam and gas generators, gas holders, deaerators, tanks, etc.
We use Netalyser to quantify answers to questions of transient behaviour arising in the course of the design and operation of large power stations, industrial process gas or steam systems, waste heat recovery or of hydraulic networks handling such things as condensate recovery, water-treatment reticulation, fuel-oil distribution, heat exchanger networks or tank farms.
0ur tools are ideally suited to the systematic analysis of “what-if” situations which can arise as a consequence of equipment malfunction, altered operating procedures, plant or control system modifications or unexpected or unintended external influences. Detailed analysis of transient events can be undertaken with high dynamic accuracy. The steady-state conditions achieved at the conclusion of the transient will accurately reflect mass and energy balances throughout the plant.
We also use Netalyser for building operator training simulators for power plants and process plants.
The Netalyser simulation suite consists of five modules:
- Netalyser SMS, the simulation management system;
- Netalyser Modeller, a configurable modelling system with an extensive library of component models;
- Netalyser HMI, a configurable user interface, including measured value displays, trend graphs and alarms;
- Netalyser DCS, a full functionality, configurable control and automation system;
- Netalyser IF, a communications interface to third party process control systems.
Netalyser runs on PCs under Microsoft Windows. It is scalable so that multiple DCS, HMI and or Modeller modules may be deployed on one or more machines to achieve the required performance and functionality. Modules communicate using a proprietary TCP/IP based protocol.
Netalyser SMS
SMS is used to manage the operation of the simulator when conducting training sessions or engineering analysis studies. It provides the user with a comprehensive set of interactive facilities for:
- running the simulator (step, run, freeze, speed up, slow down)
- managing snapshots (permanent or factory installed, user created) and backtracks
- accessing the simulator database
- managing users (administrators, trainers, trainees)
- accessing extensive model and system diagnostics
- managing interventions
A feature of the SMS is the Intervention Manager (or enhanced malfunction facility) which provides access to a virtually unlimited number of malfunctions from drop-down menus. In principle, any model measurement or any driven device can be failed for a variety of reasons - almost anything reasonably predictable is possible. It includes a Scenario Editor for creating, editing and saving chains of events (which reflect realistic event chains) to obtain almost any desired outcome.
Our approach is based on the principle that a malfunction must be introduced as a “primary cause”, that is, the malfunction is the initiating cause of the event and not merely a symptom. For example, a high bearing temperature is not a malfunction in itself but rather a symptom of several possible causes.
Netalyser Modeller
Fundamental to successful simulation outcomes is model accuracy.
Modeller allows simulations to be assembled as a collection of lumped plant component models (such as tanks or furnaces) connecting to networks of standard building block components (pipes, valves, pumps, etc).
Individual component models are configured using real plant data such as physical dimensions, material properties, geodetic layouts and working fluid properties. This information is stored in the simulator database along with component interconnection details.
The core of Modeller is its high-speed computation engine. Specifically developed for this application, it is an advanced algorithm which automatically builds and then solves the network system matrix equations that describe the complex time-varying and spatially distributed behaviour of each complete network. Unlike other simulation methods which build up a complex system of discrete plant components, Modeller builds a set of matrix equations directly from the network topology information and plant data in the simulator database. Spatially-distributed effects are included by the representation of each network element as a contiguous set of control volumes or cells.
Two coupled matrix equations are formed, one solving for the pressure/flow distribution and one for the enthalpy/temperature distribution simultaneously at all points (cells) throughout the network. The coefficients of the two matrix equations and each interfacing component are computed directly from plant data, using sound physically-based models, supported by well-established and documented engineering correlations for pressure loss and heat transfer coefficients, together with routines for the computation of the transport and thermodynamic properties of the working media. Each coefficient is computed as the product of two elements, one being a function only of the physical design and materials of the plant that is computed once during initialisation of the simulation, and the other is recalculated each computation cycle and includes the non-linear process state and thermodynamic dependencies of the equation coefficients.
Modeller high-fidelity models have been proven in numerous simulation studies and simulators. Cost effective simulations need to be assembled and matched to their reference plants quickly and accurately to meet tight project schedules. Modeller facilitates the rapid configuration and validation of plant models, using existing plant piping and duct layout drawings, and standard equipment and rating data to define all physical dimensions and operating parameters.
Many of the mathematical methods forming the basis of Netalyser Modeller closely follow the techniques described in this publication.
Netalyser HMI & DCS
HMI and DCS are fully configurable tools that provide Netalyser with its own control and visualisation functionality as an alternative to an interface to a third party emulated DCS as might be used in a site-specific replica simulator, or as a site-specific DCS development environment. They can be used to create a fully integrated, project-specific automation and control system without the cost or advance supply of a DCS emulation.
HMI provides a comprehensive operator interface for control of a simulated plant. Multiple HMI screens can be configured interactively to create animated plant flow schematics, in line with normal industry practice. These can include a wide range of plant symbols (tanks and other vessels, pipes, valves, motors etc), controller faceplates, individual and group measurement displays, control sequences, alarm and trend graph displays and other symbols required by the application. Active elements of the HMI displays are linked directly to measurements sourced directly from the simulation models or to DCS elements such as standard actuator and motor control blocks.
DCS provides a comprehensive set of control function blocks covering the usual analog controller and mathematical functions and a full set of logic combination, comparator and timer functions. DCS easily handles many hundreds of control schematics of any complexity, including analog and logic elements, complete with their “plant” interfacing and signal processing elements. They are composed graphically and converted directly into runtime configuration files with a single key stroke.
Both DCS and HMI are configured and run as independent processes linked by a common interface via which they exchange measurement and command signals under control of the SMS. Some of these linkages are implicit at the low level of standard interface blocks while others are user configurable.
For engineering design and analysis studies HMI and DCS are used to implement a simulation automation system which reflects the control and operating principles of the reference plant. This allows automatic control of the simulated plant as well as operator interaction with the simulation to create operating scenarios and manipulate control set-points, the display and trending of measured variables and the generation of alarms.
Netalyser IF
IF is the interface module that handles the exchange of data between Netalyser modules and any virtual or stimulated third party DCS and/or HMI that may form part of a simulator. It supports simultaneous connections with up to four separate OPC servers, and can readily accommodate custom drivers for other DCS protocols.