Winner of the 2022 bronze vector award: This bucket wheel device for extracting coal is used in Banawala, India. The stacker reclaimer moves on a 700m rail structure and must be reliably supplied with power on this route. But the cable drum for supply increasingly allowed failures and damage to the exposed sensitive high-voltage cable, so the operator was looking for a more maintenance-friendly alternative. Today, the system uses an energy chain that, together with cables and monitoring sensors, has significantly increased reliability and safety during operation.
Talwandi Sabo Power Limited (TSPL) is a coal-fired power plant in Banawala, India. Stacker reclaimers are used here in bulk material handling to mine and load coal, whereby the coal-fired power plant is used directly with the coal to generate energy. Since it is central to the continuous operation of the coal-fired power plant, failure is not an option.
Stacker reclaimers are a combination of two different machines, where the stacker transports the coal to a heap and the reclaimer sends it to the boiler of the power plant as required.
In order to travel flexibly to different positions during dismantling, the entire stacker reclaimer constantly travels on a huge 700m rail route. The moving cable guide of the machines and thus the power supply has always been ensured by a cable reeling drum (CRD) up to now. Since the energy supply system is connected via various individual components, e.g. motor, gearbox, switch, slip ring and bearings, repeated maintenance measures have been indispensable for the operator. Attention was also paid to the exposed high-voltage cable (11kV), the outer jacket of which could be damaged by the coal transported in the plant. During the 3-year period of operation, the cable diameters were therefore increased, which led to increased weight and increased cable sagging. The drive of the cable drum was burdened as a result, ran only unreliably and led to voltage problems in the cables. The sometimes severe damage to the cables led to unreliable operation of the system and high maintenance costs.
Due to the repeated problems and increased downtimes of the entire plant, the operator made more enquiries for a suitable solution. In spring 2019, a project to overhaul the cable guidance system was finally launched by the operator together with an igus project team. Close contact, which lasted for several months, covered the entire process from project design to the final installation of the new cable guide. The core of the new solution is a huge energy chain with a travel of 670m. This has set the current world record, as it is the second plastic energy chain worldwide with this travel length.
Since such a superlative solution can of course also lead to uncertainties, the proposed chain - an E4/4 type 5050RHD roller energy chain sample - was extensively tested in advance in our in-house laboratory.
The cables are guided safely inside the chain and are better protected against external influences. Our chainflex cables, designed for moving applications and designed in conjunction with our energy chains, were also used in the new cable guide. In order to provide additional planning security for these dimensions, the entire cable guide is supplemented by smart plastics, i.e. intelligent sensors in combination with energy chains.
So-called iSense modules ensure continuous condition monitoring by sensors measuring the prevailing push/pull forces along the chain. These data are evaluated via a module in the switch cabinet and can perform actions, such as shutting down the system, if a limit value is exceeded. Damage to the cable guide can thus be prevented before it occurs.
Overall, the interplay of energy chain, cables and sensors has resulted in a solution that was able to make a major leap forward in terms of plant availability, durability and safety during operation. The plastic energy chain saves weight, simplifies cable guidance and saves the operator high maintenance effort and costs.