Overview
IEC TS 62738:2018 - Ground-mounted photovoltaic power plants – Design guidelines and recommendations - provides practical guidance for the design, installation, commissioning and maintenance of grid‑connected, ground‑mounted PV power plants. The technical specification covers utility‑scale installations made up of multiple PV arrays directly connected to a medium‑voltage or high‑voltage grid, where access is restricted to qualified personnel and continuous safety monitoring is in place. IEC TS 62738 complements the general PV design requirements in IEC 62548 by focusing on issues that distinguish large ground‑mounted plants from smaller residential or commercial systems.
Key topics and requirements
The document addresses technical and safety areas critical to utility‑scale PV projects, including:
- PV array configurations - fixed tilt, adjustable tilt, single‑ and two‑axis trackers, central vs string‑inverter layouts, and multiple sub‑array arrangements.
- Earthing and d.c. system options - un‑earthed, high‑ohmic earthed and functionally earthed d.c. circuits and their design implications.
- Cable routing and selection - above‑ground trays, trenches, direct burial and ducting strategies for d.c., a.c. and communications cables, with attention to mechanical protection and segregation.
- Overcurrent protection - string, combiner, sub‑array and array protection philosophy, device selection and sizing for large PV collections.
- Equipotential bonding - techniques for bonding over extensive array fields to reduce touch and step potentials.
- Lightning, surge and fire protection - measures to mitigate lightning strikes, overvoltage events, insulation faults and arcing risks.
- Medium/high‑voltage systems - collection system topologies (radial, loop), transformer selection and installation, switchgear and utility interface considerations.
- Selection and erection of equipment - combiner boxes, disconnectors, cables, trackers and related components appropriate for power‑plant duty.
- Commissioning, monitoring and maintenance - acceptance testing, continuous monitoring requirements and documentation/labeling expectations.
- Inverter application guidance - Annex A summarizes central vs string inverter advantages, sizing considerations and PV‑to‑inverter power ratios.
Applications and users
IEC TS 62738 is intended for:
- PV plant designers and electrical engineers
- EPC contractors and construction managers
- Utility engineers and grid interconnection planners
- Asset owners, plant operators and O&M teams
- Safety officers and regulatory bodies evaluating large ground‑mounted PV projects
Use this TS when developing site layouts, electrical collection systems, protection schemes, installation specifications and commissioning/acceptance procedures for utility‑scale PV power plants.
Related standards
- IEC 62548 - referenced for safety and design requirements applicable to PV systems; IEC TS 62738 interprets and extends those requirements for ground‑mounted PV power plants.
Keywords: IEC TS 62738, ground‑mounted PV power plants, PV power plant design guidelines, array configurations, cable routing, overcurrent protection, equipotential bonding, medium voltage, high voltage.