APCS of the boiler unit No. 1 of BKZ-420 type of CHPP-4 (OJSC “Omskenergo”)

The APCS is based on DCS¹ “Tornado-M” and designed for process automation of the boiler unit in all operating conditions. The automation covers all monitoring and control functions. The system size is over 1600 I/O channels.

Technological object

Technological object of automation is a steam boiler of BKZ-420-140 drum type with natural circulation and capacity of 420 t / h, with steam parameters: P² = 13.8 MPa and T³ = 550 °C, which is designed for work on a gas and coal fuel. The boiler is equipped with four coal-pulverization systems with tangential hammer mills, two blower fans and two exhausters. 

According to the developed modernization project, the boiler is put into the mode of seasonal burning of two fuel types: ekibastuz coal and natural gas.

Stages of work

Work on this project was started by leading technological and design organizations in December 2002. The boiler commissioning in trial operation on gas fuel took place on March 24, 2004.

While working on APCS development and integration at Omsk CHPP-4 the specialists of “Tornado Modular Systems” company and the leading design & technological companies (CJSC “SibCOTES” (Novosibirsk), OJSC “Novosibirsk Teploelectroproekt” and OJSC “VNIPIENERGOPROM” West-Siberian branch (Omsk)) performed the following steps:

As always, big attention has been given to Customer’s staff training.

In addition, the specialists of “SibCOTES” company with the participation of "Tornado Modular Systems" carried out complex assembling & commissioning of the APCS.

About the project

The project of the boiler unit gasification and its equipping by industrial APCS was performed as part of the technical re-equipping program of OJSC “Omskenergo”.

The control system of fuel feeder based on DCS Tornado” completely automates the delivery path and burning of the fuel, performs automatic monitoring and control of the fuel feeder parameters of the boiler unit when different fuel types are used.

The special characteristics of the approach towards the of APCS information support of the boiler unit exclude the influence of the “human factor” in fuel feeder running.

The control system provides protection from unauthorized access and incorrect fuel feeder control, keeps a detailed record of all actions of the service staff, failures and errors of software and hardware, deviations of the technological parameters from norms and malfunctions of the fuel feeder; thus ensuring transfer of accurate and comprehensive data to the staff. This allows the service staff to carry out an analysis of trends and reasons for changes of the fuel feeder operation as well as to carry out competent and accurate correction of the technological process parameters.

Description of the system

The Integrated automation system based on DCS “Tornado” is designed to provide of sufficient, reliable and up to date information on the fuel feeder parameters and the technological equipment state to the staff and to perform all primary monitoring and control functions at the object. The system provides the following full-scale monitoring and control functions of the boiler unit:

Information:

• collection, processing, entry and storage of input information on technological parameters of the manufacture and actions of the system and staff;

• performing all data processing tasks related to maintenance and optimization of the fuel feeder;

• providing complete and reliable information about the fuel feeder to the staff (a full visualization of the technological equipment and the fuel feeder state).

Control:

Service (which provide the system efficiency): DCS “Tornado” is based on the conventional hierarchical scheme, which considers the specific of conditional partition of automation object into units. The system consists of the upper and lower levels.

The lower level performs collection, entry and processing of analog and discrete information in the DCS, formation and execution of controlling actions for the actuators of the technological equipment, provides performance of the protection, interlocks and control functions in accordance with a task. The lower level of the system is based on the controllers of the functional units (CFUs), connected by the duplicated Ethernet network, and the switching and auxiliary equipment.

The main system upper level provides interaction of the process control operators and engineering staff with controlled technological equipment of the boiler unit and organizes the system operation and preparation of data arrays for the usage by the non-operational administrative & technical staff of the station. The DCS upper level is constituted of the duplicated automated workstations (AWSs) of operational and non-operational staff, servers of databases and applications, which are connected by the duplicated Ethernet network.

In addition to the main system, the backup control system is implemented using non-programmable automation tools. The backup control system is designed for unloading or shutdown of the boiler in the case of a failure of the main control system.

The DCS microprocessor-based platform consists of modern MIF⁴-controllers, which are characterized by high availability ratio and improved fault tolerance.

The technological controllers are designed as a crate of 6U format with installed electronic modules and submodules of remote terminal units (RTUs), which provide conversion of the electrical signals from / to the technological equipment to the digital code. The main element of the controller is MIF-modules manufactured by “Tornado Modular Systems” company, adapted for use in the automation tasks of the major objects of heat-power engineering. The MIF-modules are based on a Motorola 68360 processor of 6U format with OS-9 real-time operational system. The duplicated CAN-bus network is used for communication between the controller modules within one controller and between the crates which belong to one controller. The duplicated CAN-bus network provides the possibility of “hot” replacement of the modules without shutdown of the controller.

The functional sub-modules of ModPask architecture are used as RTUs. These modules perform the discrete I/O functions, analog-to-digital conversion, filtering, digital-to-analog conversion and other functions of communication with the “field” level. Each MIF-module contains up to three functional ModPack sub-modules.

The functions of direct connection of cables from the sensors and technological equipment, primary signal processing, status indication, galvanic isolation, electric power supply of sensors and setting of connection schemes are performed by the Field Interface Units (FIUs). Connection of the field cables to the FIUs is implemented without intermediate converters, adapters and assemblies of the intermediate terminal blocks.

The technological controllers, FIUs and auxiliary communicational elements are arranged in double-sided support cabinets with the IP55 level of protection from external factors. For connection with the upper level of the DCS in each of the controllers dedicated MIF-modules are available; the MIF-modules provide connection with the duplicated Ethernet network, which connects all the DCS elements.

The AWSs, servers and controllers are combined by duplicated Ethernet network that provides full interchangeability of the AWS functions and enables to receive access to control of the technological process of the boiler unit from any worksite. The network is configured as duplicated for reliability improvement. Each of the DCS elements, which are connected to the network, has two Ethernet interfaces.

All DCS upper level components are energized from an uninterruptible power supply system (UPSS) installed in the CFU⁵ cabinets. The upper level UPSS system is built on two uninterruptable power supplies, the outputs of which form the AC duplicated power supply bus of 220 V voltage.

1^ Distributed control system.

2^ Pressure.

3^ Temperature.

4^ Module of intellectual functions.

5^ Controller of functional units.

 

 

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