This page contains a Flash digital edition of a book.
OILS & LUBRICATION


FEATURE SPONSOR CONDITION-BASED LUBRICATION


Given the operating conditions a wind turbine faces over a typical 20-year service life, maintenance problems aren’t a question of ‘if,’ but ‘when’. When those inevitable maintenance issues arise, windfarms are faced with the prospect of expensive crane mobilisation, lost energy production and the soaring costs of getting teams of maintenance technicians to site. The need to reduce overall operating costs is an important factor in any purchasing decision, especially now in the light of the planned withdrawal of the renewables obligation for onshore wind energy.


ASSET MANAGEMENT PACKAGES


As a result, operators are showing increasing interest in more comprehensive asset management packages - implementing combined remote condition monitoring and automatic lubrication systems, for example, which can have a positive impact on operating life and maintenance cost reduction. Specifying such a condition-based lubrication system, either on a new turbine or as a retrofit, is becoming an attractive option for operators seeking to reduce running costs.


While sophisticated lubrication systems for wind turbines have typically been installed on larger turbines of 1.5MW and above, with manual lubrication costs accounting for as much as 10 per cent of the total servicing bill, they are now increasingly likely to be found on smaller turbines. Condition-based lubrication enables remotely monitored, automatic lubrication of a wind turbine’s hard- to-access bearing systems, based on real-time bearing condition monitoring, reducing the frequency of on-site service engineer visits and potentially wasteful periodic, manual lubrication.


AUTOMATED LUBRICATION SYSTEMS


The basic type of automated lubrication device is a single point gas-driven or electro-mechanical lubricator. However, while this offers a simple, easy-to-change solution, its life is normally limited to around twelve months. A more effective


REDUCES ASSET MANAGEMENT COSTS We introduce SKF, our sponsor for this feature who are regular contributors. Matt Preston, Lubrication Systems Application Engineer at SKF takes us behind the headline…


option is an automated lubrication system, combining a refillable reservoir, pump and metering devices, feeding multiple lubrication points through a network of pipes. Lubricants are applied in pre- determined volumes and time intervals by each valve, or may be progressively applied to all lubrication points while the main pump is running. Only occasional manual intervention is needed to recharge lubricant reservoirs and simple system maintenance as part of a normal routine. When interfaced with a remotely accessible condition monitoring system, which uses vibration and temperature sensors mounted on a turbine’s main shaft bearings, drive train gearbox and generator to collect, analyse and compile a range of operating data in real-time, condition-based lubrication enables automatic applications of lubricant as and when they are necessary - and independently of any existing time-based cycle. A remotely located condition monitoring specialist can use the vibration/temperature data analyses to set appropriate alarm settings that trigger additional or less frequent lubrication cycles and volumes, as necessary.


SEPARATE INDEPENDENT LUBRICATION SYSTEMS


A large wind turbine will typically have up to five lubrication systems, covering pitch bearings and gears, yaw bearings and gears, main bearings, gearboxes and generators. Each of these systems will be subject to different stresses and will therefore have different lubrication requirements; for example, main bearings are subject to fluctuating thrust loads, and generator bearings to high and low speed axial loads. Additionally, the turbine has to withstand demanding environmental conditions, with extremes of temperature, high and gusting winds and, in coastal locations, the effects of salt corrosion. Pitch bearings require a constant


re-supply of lubricant. The lubrication unit is mounted in the rotor, with which it continually turns, adjusting to the resulting vibration and centrifugal force. Grease pumps, such as those supplied by SKF are fitted with a grease follower plate to ensure that grease is maintained in the area of the pump elements, enabling suction even with rotation. From there, the grease arrives at the metering


16


www.windenergynetwork.co.uk


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52  |  Page 53  |  Page 54  |  Page 55  |  Page 56  |  Page 57  |  Page 58  |  Page 59  |  Page 60  |  Page 61  |  Page 62  |  Page 63  |  Page 64  |  Page 65  |  Page 66  |  Page 67  |  Page 68  |  Page 69  |  Page 70  |  Page 71  |  Page 72  |  Page 73  |  Page 74  |  Page 75  |  Page 76  |  Page 77  |  Page 78  |  Page 79  |  Page 80  |  Page 81  |  Page 82  |  Page 83  |  Page 84  |  Page 85  |  Page 86  |  Page 87  |  Page 88  |  Page 89  |  Page 90  |  Page 91  |  Page 92  |  Page 93  |  Page 94  |  Page 95  |  Page 96  |  Page 97  |  Page 98  |  Page 99  |  Page 100  |  Page 101  |  Page 102  |  Page 103  |  Page 104  |  Page 105  |  Page 106  |  Page 107  |  Page 108  |  Page 109  |  Page 110  |  Page 111  |  Page 112  |  Page 113  |  Page 114  |  Page 115  |  Page 116