Provecta was an active participant at the 2017 ISA POWID Symposium held in Cleveland, Ohio. As well as being a Symposium exhibitor, Provecta’s Mr Don Parker acted as a Session Chair, as well as presenting papers on the following topics.
- POW17-48 – Assessing Operational Risks Associated with Remote and Multi-Unit Supervision Initiatives: An Australian Case Study
- POW17-45 – Model-based Control Applications for Conversion of Constant-Pressure Drum Boilers to Sliding Pressure Operation
Abstracts for these papers can be seen below. Entire papers are available from the ISA website.
Assessing operational risks associated with remote and multi-unit supervision initiatives: an Australian case study.
Author(s):
Neil Ronan, Provecta Process Automation LLC
Donald Parker, Provecta Process Automation LLC
Keywords: operation risk, multi-unit operation
ABSTRACT (ID: POW17-048)
As operating costs of thermal power plant increase and margins reduce, some generators have successfully introduced more flexible operating arrangements following enhancements to the utility’s instrumentation, protection and automation systems. In Australia, multi-unit and unattended (roaming operator-maintainer) arrangements have been in place at several coal-fired utilities for over ten years, as well as off-site centralized operation of CGT and geographically diverse hydro-generating assets.
One recent project involves the remote (off-site) operation of a supercritical unit in combination with multi-unit operation of a four-unit drum-boiler station from a centralized control room at the four-unit station. Planned operating arrangements, depending on plant state, include single, dual, and remote unit supervision.
The authors and other company team members were involved in reviewing identified operational risks and developing the strategy and plan for implementation of this change. Elements included: alarm management, instrumentation integrity, plant protection philosophies, modulating control and trip-to-manual philosophies, level of sequence automaton, control room layout and ergonomics.
This paper discusses the approach, risks and initiatives taken to achieve the operating goals. The process for maintaining functional safety and practical outcomes of the safety-instrumented systems design, as applied to highly self-protecting plant, are presented.
Model-Based Control Applications for Conversion of Constant-Pressure Drum Boilers to Sliding Pressure Operation
Author:
Don Parker, ME, Principal Engineer, Provecta Process Automation LLC.
Keywords: Sliding Pressure, Boiler Controls
ABSTRACT (ID: POW17-045)
Many coal-fired constant-pressure drum boilers are still in operation. Often originally designed for operation in the 80-100% load range, they are now becoming subject to the new market imperatives of wider range operation with faster ramp rates.
Several advantages exist in moving to sliding pressure, including improvement in average heat-rate and reduced deviations in HP turbine inlet temperature during ramps. However, several issues can impede the introduction: quantifying the cost-benefit; managing the fast change in fuel required for overfiring (potentially increasing carbon in ash); predicting expected changes in attemperating spray flow requirements and additional thermal stresses caused by both saturation temperature changes at the drum and from fast firing changes during load reversals in AGC.
This paper presents the results of an analysis of unit heat-rate improvement for a US 520MW CE boiler and a model-based co-ordinated control design implemented on several sliding pressure conversions to minimize fuel change rates and thermal stresses by using boiler storage effectively. Simulation results comparing the dynamics of the two modes of operation and field data from an Australian utility are also presented.
Jun 2017
