Diamond Power Infrastructure Limited (DPIL) has received a Letter of Award (LoA) worth ₹179.43 crore, inclusive of GST, from Adani Electricity Mumbai Limited (AEML) for the supply of specialised medium-voltage (MV) and low-voltage underground power cables for Mumbai’s distribution network.
The award covers approximately 871 km of cables, comprising 33 kV and 11 kV medium-voltage cables along with associated 1.1 kV low-voltage cables. The prices include packing and forwarding as well as freight and transit insurance. A formal purchase order is expected to be issued by AEML against the Letter of Award.
This marks the third consecutive year that DPIL has received the contract from AEML. According to the company, the repeat award reflects AEML’s assessment of its catenary continuous vulcanisation (CCV) manufacturing capabilities, in-house testing infrastructure and delivery performance on the Mumbai network. DPIL is also an established supplier of power cables to BEST (Brihanmumbai Electric Supply & Transport Undertaking).
Specialised Cable Technology for Mumbai’s Conditions
The cables covered under the award are designed specifically for Mumbai’s challenging coastal and monsoon environment. The specification includes tree-retardant cross-linked polyethylene (TR-XLPE) insulation, water-blocked conductors, water-swellable tapes for longitudinal water blocking and an HDPE outer sheath for radial moisture protection.
Mumbai’s low-lying and densely developed geography, high annual rainfall and prolonged water exposure in cable trenches, ducts and joint bays create demanding operating conditions for underground power cables. The persistent saline environment further increases the challenges associated with moisture ingress.
The specialised construction is intended to address water treeing, a degradation mechanism that can occur when moisture reaches cable insulation under sustained electrical stress. Over time, water treeing can progressively reduce dielectric strength and potentially result in cable failure.
Four-Layer Moisture Protection
The cable design incorporates multiple measures to improve resistance to moisture-related degradation. TR-XLPE insulation is formulated to suppress the initiation and growth of water trees, while water-swellable tapes expand when exposed to water and help prevent longitudinal moisture migration along the cable core.
Water-blocked conductors help eliminate internal pathways for moisture movement between conductor strands, while the HDPE outer sheath provides a radial moisture barrier with substantially lower moisture permeability than conventional sheathing materials.
Manufacturing and Testing Capabilities
DPIL manufactures these specialised cables on catenary continuous vulcanisation lines using triple-extrusion heads, dry-cure crosslinking, clean-room compound handling and controlled degassing. The company’s in-house testing infrastructure supports type, routine and special testing across its MV cable range, including partial discharge measurement.
The company said India’s medium-voltage cable demand is being supported by the conversion of urban distribution networks from overhead to underground systems, renewable power generation and evacuation infrastructure, as well as the expansion of data centres and industrial capacity.
DPIL operates an integrated manufacturing facility in Vadodara, Gujarat, and supplies specialised medium- and extra-high-voltage products to utility customers. The company considers repeat qualification with utilities such as AEML and BEST an important indicator of its position in the MV cable industry.
Order Execution
The deliveries are scheduled to commence upon manufacturing clearance at an approximate rate of 50 km per month, with the schedule subject to advancement in line with project requirements. The award has been received from a domestic entity and is in the ordinary course of business and at arm’s length.
