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505 and CPC-II upgrade project for UK Refinery

We were approached by our customer, a manufacturer and supplier of sugar, aggregates, tomatoes, animal feed, Bioethanol, TOPSOIL and LimeX in addition to generating electricity, to survey the original control equipment and recommend improvements to reliability issues. Of the large number of British Sugar factories, those used within the production of electricity use a combined heat and power generation system that produces steam and electricity used to power its factories and the excess, approximately 50MWh per factory is exported to the grid and sold to electricity supply companies.

During 2010 and 2011, one of the turbines tripped and shutdown many times causing major problems across the production processes. Our customer therefore sought a significant increase in reliability.

The requirements for the new system, conveyed to us by consist of the removal of the existing ten year old Woodwood 505 governor system and its associated hydraulic pipework and valves, and replacing with the new Woodwood 505 and CPCII mounted in purpose built panel, the CPC-II offers far great reliability than that of the originally installed CPC-I. We would also be fitting a HMI505 view for remote control and monitoring. The original Dr Horn over speed equipment became unreliable, thus was replaced with the Woodward Protech TPS over speed module.

To complete this project, engineers Jon, Karl and Chris attended site to record all information and measurements necessary for us to install the new 505 panel and CPC-II system. Our Technician Kevin worked on the cabinet at our works.

Technician Chris attended site to fit the CPC-II and complete all pipework. The original CPC bracket was in poor condition consisting of a plastic box which was worn and broken. We designed and made a new bracket for the CPC-II which was moved back to make space for the new, much more robust bracket, far more suitable for the design.

Testing

Upon completion of the all remaining elements to the British sugar upgrade, the final stage consisted of comprehensive functional testing of all components to the set, emergency stop tests, overspeed trip testing and a final testing of the turbine onload.

The ProTech TPS was tested to ensure it functioned correctly. The TPS is a 2 out of 3 system in which there are three independent modules; if any two give the same value it results in a functional output. If one module fails therefore, the system can still function and an alert of the failed module will be issued. The correct functioning of the three dual MPUs was also tested to ensure all three read correctly with the turbine turning over an electric motor at 263 RPM.

We also tested the 505 overspeed trip and the mechanical overspeed trip. The CPC-II (Current to Pressure Converter) was the final module to be tested. It is wired to the 505 control that positions the steam inlet valve to desired position depending on speed and load. All data is feeds back to the HMI enabling the status of equipment to be monitored.

Lastly we ensure a final testing of the turbine onload took place, which generated MW and exported 4MW to the National Grid. The final test was very successful and stable.

Main Propulsion Actuator for Rolls Royce Astute Class Submarine

We were asked to design and build an actuator to that would be suitable for their new class nuclear submarine project. The final product had to be a simple actuator with electronic control, designed to meet a very strict engineering specification in addition to the following requirements:

  • Anti-corrosive
  • Ability to hold high chemical content oil
  • Sufficiently rigid structure to withstand intense shockwaves.

Challenges:

The main uncertainties within this project concerned the compatibility of the product with the controls specified by the client, the nature of the actuator itself and its ability to pass the stringent shock testing, in addition to the type of materials used and their suitability for the life of product.

Solutions:

To overcome these uncertainties, all materials produced for the project were tested numerous times and chemical analyses were carried out on vital pressure components. A prototype actuator was built and extensive testing carried out in order to monitor any material failures. Throughout these procedures various redesign work was carried out, prototypes developed and a number of modifications were made in order to ensure the best possible product was offered to the customer.

Outcome:

The final testing consisted of a simulation of the submarine’s electronic control, tested under all conditions. The reliability of the product was then demonstrated to the customer and the project has so far been very successful resulting in repeat order.

Obsolete governor overhaul for national freight operator

A regular customer of ours approached us early December 2011 to book in the overhaul of two Sulzer governors which were manufactured in the early 60s.

Unlike the UG governors with which we frequently work, this Sulzer governor has no internal pump; it relies on oil pressure being fed directly from the engine. This explains the reason behind its particularly dirty state which can be seen in the pictures.

It has two solenoids; one for start-up and one for shutdown. Although it is a very basic governor in terms of its operations, it has a particularly large number of components, more so than governors more complicated than the function of this Sulzer.

Challenges

This kind of job can be particularly difficult and time-consuming, as when the governors were originally manufactured, one of the core design specifications was for it to be durable. The end result was a governor with its mechanical parts so durable that they would operate for years on end before defaulting and needing an overhaul, by which time, most customers no longer have any product information to provide with the job.

This problem is compounded by the fact that overtime manufacturers ceased making the product, so not even they can provide the necessary information. Thus, in the majority of cases, the product comes into our works with minimal technical data and no drawings. The technicians therefore have nothing to work with except the governor itself, their experience and expertise.

How do we overcome these challenges?

As the governor comes in, photos and drawings are taken to record the position and set up of all parts. The assembly of the governor is mapped out in order to assist the technician when it comes to reassembly. Our technicians do this in such a skilled way that according to their notes and drawings, if a project was put to one side, they could pick-up where they left off on a governor reassembly years after it was originally dismantled.

This, therefore, makes the process of disassembling the governor so much more important than in the case of a UG8 governor, for example, for which the technician has everything he needs to know to complete the job.

Further challenges

In some cases of obsolete governor overhaul, not only does the governor come in with badly worn parts, they may also have broken or missing parts. In the case of the two Sulzer governors, one came in with a broken ballhead assembly, made from cast iron, and for the other, the Bakelite assembly of the solenoid was broken. Both of these parts had to be remanufactured as they are no longer being made by the manufacturer.

Outcome

This is a considerably time-consuming procedure, however with very few governor overhauling companies that are willing to offer the service on such obsolete governors, we take pride in our expertise and experience that enables us to continue to offer an excellent services to customers.

Whilst we continue to enhance our facilities and expertise by constantly upgrading our equipment to cater for state-of-the art and the latest products and technology, we will never turn down these projects that represent the origins of our business. Furthermore, our engineers particularly enjoy the challenges posed by this kind of project, and like us all, revel in the satisfaction of having completed it to a high standard.

Steam Turbine Upgrade TA4 Plus Interim Emergency Governor System

Our customer, a European refiner and wholesaler of petroleum products, approached us in April 2009 to design and build a new steam turbine control to replace an old mechanical governor which had failed in service. The customer also had new control requirements for the equipment to meet their future plans for the business, in addition to seeking to improve safety and engineer usability.

Requirement:

The existing mechanical governor had to be modified in such a way that it no longer acted as a control but had a key purpose in driving the main oil lubrication pump that had to be retained.
The new electronic governor system was the Woodward 505 control and Woodward CPC-II current to pressure converter.

Application:

A new driveshaft for the oil pump drive was manufactured that incorporated a phonic wheel with three dual core speed pickups. Various blanking plates were made where mechanical control gear was mounted, utilising one of these for cable entry.
The CPC converter was mounted on the turbine and piped to the relay oil for supply and sensitive oil output for the steam valve control.
The Woodward 505 control was remote mounted next to the turbine start panel and incorporated various process meters and operational controls such as emergency shutdown, rpm indication & kW output indication.
Also used was an electronic two out of three voting overspeed trip system the Woodward ProTech G11 which is the latest self-testing, acceleration monitoring, overspeed trip device.

Result:

The replacement system was designed to include redundant back up power supplies for the control & overspeed unit and CPC converter which has replaced the old mechanical governor.

Performance testing & test tripping of the turbine proved very good along with far better performance that can now be monitored via Modbus to the turbine control room.

 

Redesign of Steam Turbine Control and New Electronic Actuator

We were approached by our customer to redesign a steam turbine control system which was necessary to overcome the reliability and safety issues that they were facing. The customer was experiencing oil leaks and linkage wear with the original equipment, consisting of a mechanical hydraulic governor.

We therefore sought a solution to deliver the amount of control they required, to eliminate all safety issues, remove original linkage which had caused major wear problems and reliability issues in addition to looking into the possibility of providing an electronic actuator that can be driven straight to the steam valve thus removing all the problematic interface and damage suffered by the old governor.

Challenges:

There were a number of potential problems and uncertainties within this project such as how the new control would interface with the equipment provided by other suppliers, and the compatibility of older equipment with the new, faster actuator.

Solutions:

A new control was configured to replace the old pneumatic system; this had to be designed in such a way as to ensure its compatibility with the control panel controlling the compressor end driven by the steam turbine. Furthermore, the actuator used for the retrofit was designed exclusively for this application and manufactured to fit in with the original steam valve assembly.

Upon completion of the design phase, a full demonstration was set up to evidence the functionality. This took place with the customer present and is a particularly significant stage due to the fact that the turbine is a critical set; thus, any downtime incurred entails a significant loss to the customer.

During the testing and installation stages, many design changes had to be made in order to meet the customer requirements.

Solutions:

The first year post installation and commission was trouble free, however the customer experienced a problem the electronic actuator which was then examined. Any problems that the customer faced were readdressed as required.

Vickers Control Valve Overhaul

We regularly maintain and overhaul equipment for one of the UK’s leading integrated power and gas companies. In October 2010, they asked us to overhaul two Vickers control valves, fitted to a 500mW Parsons turbine, in addition to overhaul a Parsons main turbine electro-hydraulic valve assembly and various safety shutdown trip blocks.

Work required:

The Vickers control valves are electro-hydraulic actuators, which had to be stripped cleaned and inspected as per our overhaul process. The electronics had to be rebuilt within our retrofit department, in addition to having to rebuild and certify the new electronic heads.

To complete the Parsons main turbine electro-hydraulic valve assembly overhaul, the main pilot valves had to be completely remanufactured due to contamination within the oil system leading to severe corrosion of the controlling pilot valve.

Outcome:

Due to our successful completion of a number of jobs to a high quality standard, we now regularly service one of the main generator sets consisting of four turbines transporting energy to the national grid. This work takes place routinely to fit around the needs and downtime plans of their machinery.

For more information on our overhaul process please see our overhaul page in which you will fine a video on our overhaul process, or see our electronics overhaul page.

Redesign and Upgrade of Steam Turbine Governor Control System

This waste site, committed to the principle of sustainable waste management, recycle compost and recover value in the form of electrical energy produced from four 12.5MW steam turbines.  EGS was approached in May 2008 to attend their site and survey their original Woodward governing equipment which was around 35 years old.

We were given a list of problems posed by their existing system, the most significant of which were damage caused by out-of-sync manual breaker closure resulting in considerable loss of generation during repairs. In addition to this there are further requirements which could not be achieved efficiently by the old hydraulic governor system installed, such as automatic starting run up and synchronisation, pressure control,  power management, mains monitoring and G59/2 protection and HMI display and historical data logging of parameters and alarms.

Aim:

The aims of the project were therefore:

  • To improve reliability and gain a further efficiency on the generation of electricity from their site.
  • To improve efficiency of the steam header pressure control.
  • To enable further advancements using electronics, which would not be possible with the old mechanical governing systems
  • To significantly improve safety onsite; which also encompasses monitoring and trending

Stages and challenges:

A completely new system was designed and installed using the Woodward Peak 150 which collects the speed signal from a custom designed and manufactured phonic wheel and speed probes, sending valve position commands to the Woodward CPC current to pressure converter. This in turn provides a sensitive oil signal directly to the steam valves.

The power management is taken care of by the installed Deif GPC units on each generator and on both of the main feeders; these Deif units are communicating through RS485 to the HMI package that is loaded into a dedicated panel mount PC.

With the core parts of the new system manufactured at our works, a full factory test was carried out during which any problems can be resolved. One main issue raised was that the existing steam valves could not cope with the new faster response governing system. These valves were then overhauled by ourselves using tighter clearances on the sensitive control lands, various tests had to be carried out in order to verify performance and reliability.

Upon installation of the new system, various modifications were made to suit the customer’s changing requirements, commissioning each completed set within the turnaround period. With the equipment up and running the customer could identify other potential advantages which could be incorporated within the new system.

Solutions:

The main challenges posed by the project resulted from the combination of new and older parts. To overcome these issues, extensive pre-testing of each and every component of the new design system was necessary. All electronics were also tested at our workplace include hot soak tests for electronic components.

A test stand was manufactured uniquely for this project to enable the testing of steam valves away from the main turbine; this was to alleviate the high costs that would have occurred had we tested on site.

Outcome:

The aims and goals of the project were met and the customer proved to be very satisfied demonstrated by our continuing close relationship with them for on-going support or training required.