WG 3 - TC 82/WG 3

IEC TS 63265:2022 outlines methods that can be utilized to ensure reliability throughout the PVPS project phases. It is derived from a management motivation for long lasting and cost-effective energy performance, energy production, secure production and revenue, and safe function. The application of reliability practices in this document is designed to be practical and reduce the costs of unreliability. This document further identifies and defines a normative minimum set of processes and tools to meet the requirements of this document.
Key objectives of this document are to inform users of reliability tools and assessment methods (historic, predictive, and analytical) that can satisfy the stakeholders needs for dependable PV Power System (PVPS) operation. This document provides a fundamental process for ensuring reliability needs can be understood and met. IEC TS 63019 addresses availability which is a higher-level metric that combines reliability and maintainability, and it complements this document as a key normative standard. It should be used in combination with this document.

IEC 61724-1:2021 is available as IEC 61724-1:2021 RLV which contains the International Standard and its Redline version, showing all changes of the technical content compared to the previous edition.
IEC 61724-1:2021 outlines terminology, equipment, and methods for performance monitoring and analysis of photovoltaic (PV) systems. It also serves as a basis for other standards which rely upon the data collected. This document defines classes of photovoltaic (PV) performance monitoring systems and serves as guidance for monitoring system choices. This second edition cancels and replaces the first edition, published in 2017. This edition includes the following significant technical changes with respect to the previous edition:
- Monitoring of bifacial systems is introduced.
- Irradiance sensor requirements are updated.
- Soiling measurement is updated based on new technology.
- Class C monitoring systems are eliminated.
- Various requirements, recommendations and explanatory notes are updated.

IEC TR 63292:2020 continues the effort started with the availability technical specification (IEC TS 63019). Availability is closely related to PVPS operational capability, health and condition and to produce energy and is a real-time or historical measure. The availability of a system or component is impacted by contractual and non-contractual reliability specifications, maintenance metrics and a corresponding maintenance and repair strategy, and also external factors such as site environmental and grid conditions. The intention of this document is to be a precursor examination of the reliability issues for further address in a task to produce an IEC Technical Specification on this topic.
While this document identifies reliability tools, topics and procedures, there are commercial products available to perform analyses and there is no assessment of those tools or to provide recommendations for one tool over another in this document.

IEC 62446-2:2020 describes basic preventive, corrective, and performance related maintenance requirements and recommendations for grid-connected PV systems. The maintenance procedures cover:
- Basic maintenance of the system components and connections for reliability, safety and fire prevention
- Measures for corrective maintenance and troubleshooting
- Worker safety
This document also addresses maintenance activities for maximizing anticipated performance such as module cleaning and upkeep of vegetation. Special considerations unique to rooftop or ground-mounted systems are summarized.

IEC TS 63019:2019 provides a framework from which the availability metrics of a PVPS can be derived and reported. It describes how data are categorized and defines generic information categories to which time can be assigned for a PVPS considering internal and external conditions based on fraction of time, system health, and condition by specifying the following:
- generic information categories of a PVPS considering availability and production.
- information category priority to discriminate between concurrent categories.
- entry and exit point for each information category to allocate designation of time.
The PVPS comprises all photovoltaic (PV) modules, inverters, DC and AC collection systems, grid interconnection equipment, the site, its infrastructure, and all functional service elements. Formulas in this document provide normative guidance for standardization. Beyond that, it is not the intention of this document to specify exactly how other undefined, time-based availability metrics shall be calculated. The annexes are examples and guiding principles for developing methods for calculation and estimation of availability metrics, subject to the knowledge and concurrence for use by the involved stakeholders. Estimates and calculations also have recommendations on how they are to be used as part of the informative function.

IEC TS 62738:2018(E) sets out general guidelines and recommendations for the design and installation of ground-mounted photovoltaic (PV) power plants. A PV power plant is defined within this document as a grid-connected, ground-mounted system comprising multiple PV arrays and interconnected directly to a utility’s medium voltage or high voltage grid. Additional criteria is that PV power plants are restricted from access by non-qualified persons and are continuously monitored for safety and protection, either by on-site personnel or by active remote monitoring. Technical areas addressed are those that largely distinguish PV power plants from smaller, more conventional installations, including ground mounted array configurations, cable routing methods, cable selection, overcurrent protection strategies, equipotential bonding over large geographical areas, and equipment considerations. Safety and design requirements are referenced to the applicable requirements of IEC 62548 to address distinct differences relative to the design requirements for residential, commercial and other non-power plant applications.

IEC 62446-1:2016 defines the information and documentation required to be handed over to a customer following the installation of a grid connected PV system. It also describes the commissioning tests, inspection criteria and documentation expected to verify the safe installation and correct operation of the system. It is for use by system designers and installers of grid connected solar PV systems as a template to provide effective documentation to a customer. This new edition cancels and replaces IEC 62446 published in 2009 and includes the following significant technical change with respect to IEC 62446:2009: expansion of the scope to include a wider range of system test and inspection regimes to encompass larger and more complex PV systems.

IEC TS 63049:2017(E) provides the minimum activities deemed necessary to implement an effective quality assurance program for the managing and reducing of risk in the installation and operation of photovoltaic (PV) systems. This document defines requirements for certifying that an entity has and uses a quality assurance program to prevent, or reduce errors and learns from any new errors in installation, operation and maintenance of a PV system. The object of this document is to provide more confidence in the performance and reliability of certified PV systems. By being installed and operated under a Quality Assurance program in accordance with this document, PV systems are expected to operate as designed and as expected based on product warranties.

IEC TS 62446-3:2017(E) defines outdoor thermographic (infrared) inspection of PV modules and plants in operation. This inspection supports the preventive maintenance for fire protection, the availability of the system for power production, and the inspection of the quality of the PV modules. This document lays down requirements for the measurement equipment, ambient conditions, inspection procedure, inspection report, personnel qualification and a matrix for thermal abnormalities as a guideline for the inspection.

IEC 61724-1:2017 outlines equipment, methods, and terminology for performance monitoring and analysis of photovoltaic (PV) systems. It addresses sensors, installation, and accuracy for monitoring equipment in addition to measured parameter data acquisition and quality checks, calculated parameters, and performance metrics. In addition, it serves as a basis for other standards which rely upon the data collected.

IEC TS 61724-2:2016(E) defines a procedure for measuring and analyzing the power production of a specific photovoltaic system with the goal of evaluating the quality of the PV system performance. The test is intended to be applied during a relatively short time period (a few relatively sunny days). The intent of this document is to specify a framework procedure for comparing the measured power produced against the expected power from a PV system on relatively sunny days.

IEC 62548:2016 sets out design requirements for photovoltaic (PV) arrays including DC array wiring, electrical protection devices, switching and earthing provisions. The scope includes all parts of the PV array up to but not including energy storage devices, power conversion equipment or loads. An exception is that provisions relating to power conversion equipment are covered only where DC safety issues are involved. The interconnection of small DC conditioning units intended for connection to PV modules are also included. The object of this document is to address the design safety requirements arising from the particular characteristics of photovoltaic systems. Direct current systems, and PV arrays in particular, pose some hazards in addition to those derived from conventional AC power systems, including the ability to produce and sustain electrical arcs with currents that are not greater than normal operating currents.

IEC TS 61724-3:2016(E) defines a procedure for measuring and analyzing the energy production of a specific photovoltaic system relative to expected electrical energy production for the same system from actual weather conditions as defined by the stakeholders of the test. The energy production is characterized specifically for times when the system is operating (available); times when the system is not operating (unavailable) are quantified as part of an availability metric. The aim of this technical specification is to define a procedure for comparing the measured electrical energy with the expected electrical energy of the PV system.
The contents of the corrigendum of February 2018 have been included in this copy.

IEC 61829:2015 specifies procedures for on-site measurement of flat-plate photovoltaic (PV) array characteristics, the accompanying meteorological conditions, and use of these for translating to standard test conditions (STC) or other selected conditions. This new edition includes the following significant technical changes with respect to the previous edition:
- it addresses many outdated procedures;
- it accommodates commonly used commercial I-V curve tracers;
- it provides a more practical approach for addressing field uncertainties;
- it removes and replaces procedures with references to other updated and pertinent standards, including the IEC 60904 series, andIEC 60891.

IEC 62253:2011 defines the requirements for design, qualification and performance measurements of photovoltaic (PV) pumping systems in stand-alone operation. The outlined measurements are applicable for either indoor tests with PV generator simulator or outdoor tests using a real PV generator. This standard applies to systems with motor pump sets connected to the PV generator directly or via a converter (DC to DC or DC to AC).

Applies to utility-interconnected photovoltaic (PV) power systems operating in parallel with the utility and utilizing static (solid-state) non-islanding inverters for the conversion of DC to AC. Lays down requirements for interconnection of PV systems to the utility distribution system.

Verifies system design and performance of stand-alone photovoltaic systems. The performance test consists of a check of the functionality, the autonomy and ability to recover after periods of low state-of-charge of the battery, and hence gives reasonable assurance that the system will not fail prematurely. The testing conditions are intended to represent the majority of climatic zones for which these systems are designed.

IEC 61683:1999 Describes guidelines for measuring the efficiency of power conditioners used in stand-alone and utility-interactive photovoltaic systems, where the output of the power conditioner is a stable a.c. voltage of constant frequency or a stable d.c. voltage.

IEC/TS 62548:2013(E) sets out design requirements for photovoltaic (PV) arrays including d.c. array wiring, electrical protection devices, switching and earthing provisions. The scope includes all parts of the PV array up to but not including energy storage devices, power conversion equipment or loads. The object of this Technical Specification is to address the design safety requirements arising from the particular characteristics of photovoltaic systems. Attention is drawn to a project in the IEC 60364 series under joint development between IEC TCs 64 and 82, which will, when published, cancel and replace the present technical specification.

IEC 62446:2009 defines the minimal information and documentation required to be handed over to a customer following the installation of a grid connected PV system. Also describes the minimum commissioning tests, inspection criteria and documentation expected to verify the safe installation and correct operation of the system. Is written for grid connected PV systems only.