INDUSTRY: MANUFACTURING (CEMENT PRODUCTION) INVENSYS WONDERWARE

SOUTHERN AFRICA CUSTOMER SUCCESS STORY

PPC Hercules SCADA Upgrade PPC Cement chooses leading SCADA system for Hercules

Faced with a growing market demand for cement and obsolete supervisory and

control equipment at their Hercules facility, PPC decided to replace their

existing 30-year-old electrical and control systems with sophisticated

technology – a major upgrade that took more than a little courage and

commitment.

And they did so using the number one supplier in the business, as ranked by Frost &

Sullivan in 2010 – Wonderware and the company’s System Platform, InTouch (HMI),

Historian and ActiveFactory (trending, analysis and reporting) suite of solutions.

Introduction

As the leading supplier of cement in Africa’s largest economy as well as the Southern

African region, it is imperative that PPC continuously improves efficiencies at its

operations to ensure that it supplies product to the market reliably and consistently.

To maintain its market-leading edge, PPC’s Pretoria-based Hercules plant went through

a major overhaul. Given the extensive nature of this upgrade, it was critical that there

was as little interruption as possible to the plant’s operations.

The proposal included upgrading the electrical and control systems of kiln 5 and raw

mill 3 at PPC’s Hercules plant. The proposal dealt with the replacing of all Motor

Control Centre panels (MCCs) and Control Panels (RIO) to improve the standard of

MCCs, SCADA and PLC.

In short, this meant replacing a 30-year-old control centre that had served well with a

new, state-of-the-art solution that is flexible and offers the best in real-time information

management and optimised process control.

About Pretoria Portland Cement Company Limited In 2010, PPC celebrated its centenary as a JSE-listed company, joining an extremely small and elite group of listed centenarians, not only in South Africa but worldwide.

The roots of PPC, however, stretch back 118 years to 1892 when it established South Africa's first cement plant on the outskirts of Pretoria to counter the exorbitant delivered cost of cement imported from Europe. Since those early gold-rush days on the Witwatersrand, PPC has proven its ability to adapt and flourish in changing circumstances - two world wars, a global depression and several lesser recessions, the booms and busts of the cement market, and considerable political turmoil that culminated in South Africa's democracy.

If R100 had been invested in PPC shares listed on the JSE in 1910 and the after-tax proceeds of the dividends reinvested in PPC shares, the portfolio value would have been R26 million 100 years later. This represents an annual compound growth rate of 13.3% versus an annual compound inflation of 5.6%.

Today, PPC is the leading supplier of cement in southern Africa through eight cement manufacturing facilities and three milling depots in South Africa, Botswana and Zimbabwe that can produce around eight million tons of cement products each year. PPC also produces aggregates, metallurgical-grade lime, burnt dolomite and limestone.

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PPC Hercules SCADA Upgrade

Project background

The pre-engineering phase involved gathering plant

information to ascertain exact equipment installed,

determining process flow diagrams as well as updating and

redesign of electrical drawings. This enabled PPC engineers

to compile a list of equipment to be replaced as well as to

draw up a detailed enquiry document and functional design

specification. The purpose of this exercise was to minimise

any unforeseen obstacles in the tendering process and to

enable potential suppliers to offer an accurate quote. A

comprehensive tender document was then drawn up and

given to suppliers for their consideration.

PPC chose system integrator Quad Automation for the

project. “This was a multi-faceted and large project,” says

Ernie Koopmans, Director, Quad Automation. “All MCCs

would have to be replaced with modern switchgear as well

as for the PLC and SCADA system. There was a limited

version of ArchestrA already in place and this would have to

be expanded and upgraded to the latest version.”

Challenges faced with the old system

Given the scale of the overhaul, management encountered

various challenges with the previous, outdated system. The

nature of this required a fine balance between maintaining

operations and mitigating potential interruptions, while

installing new equipment – an art in itself.

Maintenance issues and obsolete equipment - Most of the

electrical switchgear and instrumentation in use was

obsolete compared with the technology available today.

This older equipment is maintenance-intensive and causes

prolonged downtime during failures, as most of the original

spares are no longer available and modifications need to

be done.

Limited expansion - Existing panels have no more room for

expansion or additions, hence retrofitting new equipment

would incur a high level of risk. In addition, where loose-

standing equipment had been introduced, irregular plant

supply had been used, thereby cluttering the walls of the

substations, jeopardising the equipment installed. Any

further expansion, such as the burning of secondary

material, would not allow newer equipment to be fully

integrated with older equipment, forcing the new

expansion to run on semi-automatic with limited control.

Inflexibility (relay control) ---- Any changes were difficult to

implement and required extensive rewiring.

Limited information - There was insufficient information on

bin and silo levels and all damper actuators used were

discontinued due to their age and spare shortages. In

addition, events were not logged which meant that cause

and effect scenarios could not be determined. Gathering of

process information was a lengthy procedure that ended

up being useless or inaccurate. This made it difficult to back

track or get enough information to implement process

changes successfully while gathering information such as

alarm and trip settings for auditors was a challenge because

there was no central storage repository for all of the

information.

Safety issues (compliancy) – The status of power

distribution in the plant was unknown in many cases while

some field instruments and relays were filled with liquid

mercury, which is hazardous to the environment and health

of workers.

Nuisance trips - Some temperature devices were hardwired

together in order to give temperature differences. When

one of the devices failed it had an influence on one or more

devices causing inaccurate readings and unnecessary trips.

Also, there were process lines and equipment that had

been decommissioned, but not taken out of the circuit.

However, some of these interlocks were still working,

causing a high risk of unnecessary stops and trips.

Limited data acquisition capability – Much of the data was

read off chart recorders (provided they hadn’t run out of

ink).

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Figure 1: Replacing 30 years of control system evolution in five weeks – before and after

PPC Hercules SCADA Upgrade

Project goals and requirements

To address these challenges, the project would have to be

ambitious, radical and have the least possible impact on

production at the Hercules plant. This would entail the

following:

Establishing a centralised control room – There would be

no more isolated sources of data

Ensuring the effective measurement of KPIs, logging and

trending – For example, cement production is a significant

contributor to global fossil carbon emissions (figure 3).

Bearing in mind the impact of cement production on the

immediate environment, PPC situated the plant as far from

Pretoria as possible in 1892. Today, PPC Hercules has been

swallowed up by the greater Pretoria metropolitan

complex, making its dust management that much more

meaningful.

Installing a distributed PLC network (based on Profibus)

and remote I/O capabilities

Translating the old system into PLC / SCADA control –

Although this sounds obvious, the implementation is not.

“And it wasn’t just the hardware,” says Koopmans.

“Perhaps the greatest challenge was migrating operators

who, for decades, have known exactly which button to push

under given circumstances to an environment that takes all

that away but still needs their understanding of the

process.”

Adding a new Historian server – Some standards had

already been established with the existing but under-

utilised ArchestrA-based system

Upgrading all Wonderware licences

Replacing all redundant electrical equipment

Installing new instrumentation

And it all had to happen during five weeks of the World

Cup starting in July 2010.

“Two years ago, the Hercules plant had ‘bits and pieces’ of SCADA control. Today, we have a complete, modern, fully integrated SCADA control solution that runs effectively and gives us reliable performance.” Njombo Lekula, General Manager, PPC Hercules

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Figure 2: InTouch screen showing an overview of the Vertical Roller Mill plant

Figure 3: Cement production as part of the global fossil carbon emissions picture

For further information contact Jaco Markwat at Invensys Wonderware Southern Africa

tel: +27 11 607 8303 | e-mail: jaco.markwat@wonderware.co.za

Implementation

It was planned that approximately 60% of work would begin

in January 2010, inclusive of MCC manufacture, new cabling

and cable racking. MCC and I/O panels were manufactured

off-site with FAT testing being overseen by PPC to ensure

that the equipment would be ready for commissioning on

delivery. As far as possible, new instruments were also

installed, but only powered-up on commissioning.

Disconnection of old MCCs took place during the planned

Girth Gear replacement in July 2010. Installation of new

MCCs, remote I/O panels and connection of new cabling

took place during this shutdown.

The ArchestrA Galaxy status shows that 101 templates were

used for 3364 instances (objects- motors, dampers, valves,

analogues, etc.). “The idea was to minimise template

design while maximising instance design to make it a

manageable environment,” says Koopmans. “Also,

standardising displays and icons contributed towards a

greater level of operator acceptance and buy-in. This

included simulating the analogue displays of the old system

which they were used to as well as filtering alarms such that

they were meaningful and prioritised.”

Benefits

• Achieved PPC objectives within time and budget

constraints

• Upgraded to the latest release of ArchestrA seamlessly,

which made best use of PPC’s existing investment

• Operator buy-in, early ownership and easier change

management through the ability to change the system

to their liking cost-effectively

• Working library and structured standards based on best

practices will save PPC from expensive experimentation

in future upgrades

• Four-screen design and navigation standard saves

operators running around the plant as they can see

everything at a glance and navigate to the necessary

information easily

Conclusion

Replacing ageing control systems with modern technology

is a complicated process because it means reinventing and

reinstalling the control structure of processes that keep the

company ticking. This means interfering with the company’s

core business operations. When manufacturing companies

undertake major upgrades and improvements, it is a

process that is planned well in advance before engineering

even begins. But, like death and taxes, that decision is

inevitable and with today’s technology and system

integrator knowhow, it is easier for companies to upgrade

now than in the past. The alternative is ... well, there really

isn’t one.

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PPC Hercules SCADA Upgrade

“For the first time in a very long while, we feel that we are in control of one of our primary production processes. Even more than that, we are now in a position to improve operations through trustworthy real-time information and trends.” Johan Saunders, Technical Advisor, PPC

Figure 4: Template example where highs and lows are dynamically set by operators on log-in. Templates were designed in consultation with operators and all graphics created with ArchestrA rather than InTouch.

“The client’s involvement in a project of this nature and magnitude is of paramount importance as is the following of a strict process of design and implementation.” Ernie Koopmans, Director, Quad Automation

Figure 5: System Topology