252 mw abb-alstholm gas und diesel kraftwerk

2020 www.adler-gmbh.com 1

252 MW ABB-ALSTHOLM GAS UND DIESEL KRAFTWERK


Technical Assessment of Overall System for Placing Equipment on the Market

1 General

The Brunsbüttel gas turbine power plant (GTPP) is located on the site of the Brunsbüttel nuclear power plant

in Schleswig-Holstein and belongs to the operator Vattenfall Europe.

The GTPP consists of four fossil-fuelled (fuel: light heating oil) gas turbines made by Brown Boveri (later ABB

and now Alstom), type BBC GT13B, with an individual capacity of 63 MWEl and a total capacity of 252 MWel.

They are operated without a waste heat boiler.

The GTPP was originally intended as a backup system to supply emergency power to the adjoining nuclear

power plant and to cover load peaks in the surrounding electricity grid. It is connected to the 50 Hz

transmission grid through the Brunsbüttel switchgear.

The plant was designed and built as a fast-start plant that can be brought up to full-load operation within

approximately 5 minutes. The overall system efficiency between the firing power at the inlet of the gas turbine

combustion chamber and the electrical power output from the generator on the outgoing line to the

switchgear of the central transformer is 27%. This relatively low value is due to the design for fast-start

capacity and the design date of the overall system (1973).

First commissioning was in 1973. The plant is presently planned to be kept in operable condition until1 May

2017.


2 Location and layout of the plant

The GTPP is located on the grounds of the Brunsbüttel nuclear power plant on the Elbe River, near

the Kiel Canal. It is installed in its own separate turbine house, along with the necessary associated

auxiliary systems.

Each pair of gas turbine sets is arranged in parallel and connected to a common exhaust stack. The

two gas turbine groups are located on opposite sides of the central corridor through the turbine house,

with their generators facing each other. The turbine house level is at the same height as the

surrounding grounds.

A gas turbine set essentially consists of a combustion chamber, a gas turbine (compressor and

turbine), a generator, and an exciter unit. There is a starter unit for each pair of gas turbines.


3 Access to the plant

The plant and its individual components are easily accessible.

The turbine platform is at the same height as the turbine house.

The shared turbine house crane, with a load capacity of 50 t, can be moved over all parts of the plant

without hindrance, which is advantageous for installation and dismantling activities. The intake

housings for the individual compressors are arranged accordingly below the turbine house crane level,

with inlets routed sideways to the walls of the turbine house.

The central corridor of the turbine house between the turbine groups leads directly to the building

entrance, which is large enough to accommodate heavy load vehicles suitable for the GTPP.


4 Main components and interfaces to other components

A gas turbine set consists of a combustion chamber, a gas turbine (compressor and turbine), a

generator, and an exciter unit, along with all associated control devices, control valves and stop valves.

The generator coolers are integrated into the housings of the individual generators. Each plant also

has an oil supply system for control, lubrication and shaft lifting, including the associated valves, oil pumps

and tanks.

The interfaces are:

• Exhaust outlet of the gas turbine after the exhaust diffuser and exhaust line to the connection flange at the

inlet to the exhaust stack. The interface is the sliding collar at the bottom of the stack.

• On the fresh air side before the compressor inlet on the connection frame of the compressor intake

housing at the outlet of the intake housing after the intake filter, above the gas turbine set.

• Fuel supply from the main valve of the fuel line and the following control valves for the combustion

chamber. The fuel line after the buffer tank belongs to the plant, along with the return line.

• Cooling water inlet and outlet before each generator cooler, at the respective stop valve.

• Electrical handover after the electrical pass-throughs and generator branch lines above the turbine sets,

before the busbars of the common central transformer system (outside the building).


The overall plant also includes:

• The starter units, the central compressed air system, the electrical switchgear for operation of the plant,

and the central control system equipment (Siemens T3000) and control console.

• The oil supply system, including the bearing oil tank and bearing oil cooler, is part of the plant.

• The fuel control cabinet for controlling the plant and the fuel pump unit.

The central transformer after the electrical busbars is not part of the sellable GTPP system.

The intake silencers and exhaust silencers, including housings, belong to the building component.


5 Relevant key technical data

First commissioning of the plant: 1973

• The rated speed of the plant is 3,000 rpm, making it suitable for a 50 Hz grid or 50 Hz operation.

• The generator is driven directly by the turbine through a rigid intermediate shaft. The speed regulator and

the dual-stage oil pump are driven by lateral intermediate gears.

• The generator stator and rotor are cooled by air, with the dissipated heat transferred to the cooling water

in the generator cooler. This cooling water is taken directly from the cooling water intake structure of the

nuclear power plant. With a cooling water inlet temperature not exceeding 25°C, a total cooling water flow

rate of approximately 265 m3/h is required for the GTPP.

• Each generator is excited by an associated thyristor unit.

• The starter sets (Unger starting method / DS induction generator driven by a DS squirrel-cage motor), one

for each pair of gas turbine sets, are mobile and have a capacity of approximately 4,000 kW each.

• The gas turbines can also be brought up to speed by the associated generators if the latter can draw the

necessary starting power from the supply grid.

• The lubricating and control oil supply is centralised. It supplies oil to the bearings, including the hydraulic

lift, as well as the plant control devices. It includes a central oil tank with a capacity of 10 m3.

• The compressor of the gas turbine has 17 stages. The turbine of the gas turbine has 5 stages. The inlet

temperature at the turbine is approximately 940°C, and the exhaust temperature after the exhaust diffuser

is approximately 444°C.

• With a cold gas temperature of 15°C (cooling air), each generator has a rated apparent power capacity of

84 MVA.

• The central control system, including the control console, was converted to the Siemens T3000 digital

control system in 2011, but the direct analog turbine control equipment was retained and has not been

further modified.


6 Mode of operation and condition of the overall plant

The GTPP was operated as a peak load system until 2013. After that it was operated as an on-call

emergency system (short-term load). That resulted in a further reduction in the operating hours per calendar

year.

• The plant is visually in very good condition. It is clean and well maintained, and the necessary labelling of

components and valves is in perfect condition. There are no externally visible signs of leakage.

• There has been no foundation settling of the overall plant over the entire life cycle to date, so there has

been no cause for internal misalignment. This can also be seen in the good to very good vibration

characteristics of the plant.

• The measured vibration data of all units yielded very good vibration values in the lower region of zone A.

However, there is no constant vibration registration by the control system, only vibration monitoring at the

individual bearing blocks.

• There have also been no external lightning strikes in the nearby electrical grid over the entire life cycle to

date, so the probability of concealed internal damage to the generators is negligible.

• Due to the mode of operation (peak load) and the very low number of equivalent operating hours, the

plant is in very good condition with low wear. This means that the negative effects of longterm operation

and material fatigue can partially be excluded because they have been effectively countered by scheduled

preventive maintenance with periodic inspections, including visual inspection through manholes.

Due to the mode of operation and life cycle, the findings from inspections and overhauls have been

limited to normal wear without unusual fringe effects.


In 2011 there was a system check by expert inspection of all turbines, which already confirmed the

conclusions of the present assessment. The findings from the system check were subsequently

corrected or put into perspective by maintenance measures.

Planned and executed inspection and overhaul intervals:

• Major overhaul every 12 years, regardless of actual equivalent operating hours

• Major inspection two years before each overhaul, to prepare for the major overhaul.

• Periodic annual visual inspections.

• Additional inspections and maintenance measures according to findings or anomalies in normal

operation.

No major significant findings arose from the individual overhauls of the gas turbine sets. All of the

findings were within the scope of normal operational wear and were suitably corrected or repaired.

Incipient cracks and damage to protective coatings were corrected. Related details can be found in

the respective finding and repair reports. There have been no findings that negatively affect the

lifetime or the life cycle.


7 Relevant data of the individual units

7.1 Gas turbine set GT 06 in group A with reference designation 06QA

During the overhaul, the turbine rotor was sent to the turbine plant in Berlin for inspection.

During the overhaul, the generator rotor was sent to the generator plant in Regensburg for inspection.

The next overhaul was omitted due to the low number of equivalent operating hours and the findings

from periodic inspection.

Last inspection before major overhaul 2001

Last major overhaul 2002

Operating hours before overhaul 518

Equivalent operating hours (EOH) up to overhaul

7,774

Total starts up to overhaul 738

Of which quick starts 112


7.2 Gas turbine set GT 07 in group B with reference designation 07QA

The next overhaul was omitted due to the low number of equivalent operating hours and the findings from

periodic inspection.




6,405




7.3 Gas turbine set GT 08 in group C with reference designation 08QA

During the overhaul the compressor diffuser was reworked in the Berlin plant to repair contour damage due to

the burn-out of permanent bolted joints.

During the overhaul the bearing shells were also taken to the Berlin plant for drilling to receive the babbit

metal temperature sensors (state of the art).

During the overhaul, the turbine rotor was sent to the turbine plant in Berlin for inspection.

During the overhaul, the generator rotor was sent to the generator plant in Berlin for inspection.




7,237




7.4 Gas turbine set GT 09 in group D with reference designation 09QA

During the overhaul, TLe 1 was replaced by reconditioned used blades from GT 08. Cracks in the turbine

heat shield were partially ground out and welded.

During the overhaul the bearing shells were taken to the Berlin plant for drilling to receive the babbit metal

temperature sensors (state of the art).

During the overhaul, the generator rotor was sent to the generator plant in Berlin for inspection.




37,512



8 Reportable and unusual incidents

At the overall system level of the GTPP: None

• Gas turbine set GT 06 in group A with reference designation 06QA: None

• Gas turbine set GT 07 in group B with reference designation 07QA: Essentially none. In 2003 there was a

fire in the burner area of the combustion chamber. The fire damage could be repaired, and there was no

consequential damage.

• Gas turbine set GT 08 in group C with reference designation 08QA: None

• Gas turbine set GT 09 in group D with reference designation 09QA: None


9 Summary and outlook

The entire plant is in exemplary condition, considering the date of first commissioning and its present age.

Because the plant has consistently been used as a peak load plant to meet corresponding needs at the site

and has very seldom been in operation, along with systematic scheduled inspection, servicing and

maintenance, it can be assumed that the components are only slightly used. Thanks to the constant

inspection measures, the components have also been spared the wear and tear normally associated with

their age and life cycle status.

After dismantling and subsequent reinstallation at a new location, with the available turbine exhaust

temperature of approximately 444°C it would be possible to retrofit the plant with a waste heat boiler in order

to utilise the waste heat and improve the overall efficiency.

There is no objection to placing the plant on the market, taking into account the age of the gas turbine sets

and the state of the art at the time of first commissioning. In this regard it should be noted that the high-level

control system was modernised in 2011, which considerably simplifies operation under present-day

conditions.


For questions please contact:

Adler GmbHTiberquelle 1

48249 Duelmen

Germany

Tel.: +49 (0)2594 9595 600

RolfAdlerMobil: +49 (0)151 121 433 [email protected]

Hans CasselmannHome Office: +49 (0)2054 870 46 34Mobil: +49 (0)160 712 44 [email protected]

www.adler-gmbh.com

252 mw abb-alstholm gas und diesel kraftwerk

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