Quality of the technical service
Measures the reliability, continuity of supply, and the voltage quality of the electric system using a set of standard metrics. Overall, it relates to the ability of the electric system to perform its functions.
The continuity of supply (CoS) measuring reliability and the voltage quality are important issues in the electricity distribution sector. In general, the quality of service is related to the commercial relations with customers and technical perspectives. According to the American Public Power Association (APPA), reliability, from a system engineering perspective, is the ability of an electric system to perform its functions under normal and extreme circumstances. Reliability indices help engineers and other operations personnel understand and demonstrate the interconnected nature of the many independent system components that make up an electric distribution system. This connection makes apparent that the system design, including construction practices, impacts reliability; from substation and distribution design to fusing schemes, various physical factors of system design impact system reliability. Among the commonly considered factors are system voltage, feeder length, exposure to natural elements (overhead or underground conductor routing), sectionalizing capability, redundancy, conductor type and age, and number of customers on each feeder
For most countries the main issues related to the technical aspects of quality of service can be grouped in two main fields of power quality:
* Continuity of supply (CoS) or supply quality is measured by the interruptions in electricity supply identifying the events during which the voltage at the supply terminals of a network drops to zero or nearly zero. These interruptions of supply are described by two quality dimensions, the number of interruptions and their duration. On a system level, most common continuity indices related to long interruptions are SAIDI (System Average Interruption Duration Index), SAIFI (System Average Interruption Frequency Index), CADI (Customer Average Interruption Duration Index), and ENS (Energy Not Supplied). Most countries use separate classifications for planned (notified) and unplanned interruptions. Across countries there is not a single standard if exceptional events (usually weather events) are included (or not) in the calculation of SAIDI and SAIFI.
* Product or voltage quality: covers a subset of possible variation of voltage characteristics from the desired values (excluding interruptions) such as: supply voltage variations; rapid voltage change; voltage swells; flickers; voltage unbalance; harmonic voltage distortions; transient overvoltage; and mains signaling voltage. For example, delivery of high-quality, flicker-free power are important considerations for industrial or commercial customers due to equipment damage and data loss. Large industrial customers that are energy intensive can suffer significant financial losses when voltage dips occur at their sites, but this is less relevant in residential customers. Measuring the voltage quality however can be a complex task due to technical difficulties to select the proper indicator and establish the limits. The Standard EN50160 gives general limits set for public supply networks and voltage disturbances; it is used in several European countries in combination with other country specific standards.
To manage these aspects in the quality of service, due to a managerial decision or encouraged by the current regulation, the search for high levels of service must be present in the following pillars: (i) quality indicators: selecting indicators to describe their performance; (ii) performance standards: level of quality that company is expected to supply; and (iii) financial incentives to void penalization for the performance below the standard.
Multiple changes in the use of electricity are requiring the electricity systems to perform in ways and in a context for which they were not designed originally, requiring new capabilities and designs to maintain historical levels of reliability. The electric system is being asked to perform in ways and in a context for which it was not designed. The result is a system that is under stress from these and other factors and which requires greater flexibility, agility, and ability to dynamically optimize grid operations in time frames that are extremely fast. As consumers demand high-quality power with high reliability to support a digital economy, power disruptions have potentially greater consequences to customers. Moreover, there is a growing expectation for a resilient and responsive power grid in the face of more frequent weather events, cyber and physical attacks.
This section focuses on the utility’s best practice processes as enablers to improve its quality of service using industry standards. The section does not focus on the specific parameters (e.g., voltage limits, methodology for calculating the indices, etc.) of each country in LAC the region, as these are determined by each regulator as per each country's technical norms. The utility’s processes related to technical quality of service are organized in two groups:
Data and statistics from the energy sector, including indicators on electricity losses can be found at the IDB energy hub.
The energy hub is constantly updated with new information.
