{"id":72104,"date":"2025-05-09T17:14:03","date_gmt":"2025-05-09T20:14:03","guid":{"rendered":"https:\/\/a3aengenharia.com\/en-us\/content\/technical-articles\/monitoring-disconnect-switches-substations\/"},"modified":"2026-04-29T09:10:35","modified_gmt":"2026-04-29T12:10:35","slug":"monitoring-disconnect-switches-substations","status":"publish","type":"articles","link":"https:\/\/a3aengenharia.com\/en-us\/content\/technical-articles\/monitoring-disconnect-switches-substations\/","title":{"rendered":"Monitoring Disconnect Switches in Substations: Requirements, Applications, and Teleassistance Solutions"},"content":{"rendered":"\n

Monitoring disconnect switches in substations<\/strong> is an increasingly common requirement in distribution network modernisation projects. More than an operational feature, this practice has become a regulatory, technical, and strategic requirement to ensure safety, availability, and traceability in mission-critical environments.<\/p>\n\n\n\n

Although simple in concept, disconnect switches play a decisive role in circuit isolation, safe network maintenance, and the reconfiguration of operational topologies. The absence of supervision or remote validation of these switching operations can lead to delays in fault response, expose operators to risk, and create inefficiencies in centralised operation.<\/p>\n\n\n\n

Based on ANEEL resolutions such as 846\/2019<\/strong>, and on best practices applied in executive projects for substations, monitoring combined with teleassistance supported by visual supervision<\/strong> transforms the operating process into an intelligent, auditable, and economically advantageous system.<\/p>\n\n\n\n

In this article, we explore the main types of disconnect switches, the mandatory nature of their remote supervision, and how teleassistance can improve field operation and safety. In the end, we show how A3A Engenharia de Sistemas<\/strong> delivers complete technical solutions for companies that need to implement this kind of system with a high degree of reliability.<\/p>\n\n\n

[elementor-template id=”24446″]<\/p>\n\n\n\n

Types of Disconnect Switches and Their Applications<\/strong><\/h2>\n\n\n\n

Disconnect switches<\/strong> are electromechanical devices designed to open or close electrical circuits under no-load conditions<\/strong>, allowing safe isolation of sections of an installation for maintenance, switching, or contingency purposes. The correct specification and placement of these switches directly influence the operational flexibility of the substation<\/strong>, the safety of field technicians<\/strong>, and the speed of response to events<\/strong>.<\/p>\n\n\n\n

Below, we highlight the main types used in distribution substations and their technical applicability:<\/p>\n\n\n\n

1. Knife-Type Disconnect Switch<\/strong><\/h4>\n\n\n\n

Use:<\/strong> Indoor or outdoor installations, depending on voltage level and project requirements.<\/p>\n\n\n\n

Characteristics:<\/strong> Visible opening through a metal blade (knife-type blade); simple, robust, and highly reliable construction. It allows easy identification of the position (open or closed), making it ideal for environments that require visual verification of isolation.<\/p>\n\n\n\n

Application:<\/strong><\/p>\n\n\n\n

In indoor environments: used in medium-voltage panels, secondary distribution boards, or control panels.<\/p>\n\n\n\n

In outdoor environments: common in substation yards, mounted on insulators, for the isolation of lines, transformers, or capacitor banks. It may be operated by a switching rod or by a motorised mechanism.<\/p>\n\n\n\n

    \n
  • Tripolar knife-type switches<\/strong>, mounted on metallic structures or insulators;<\/li>\n\n\n\n
  • Used in substation yards for the isolation of incoming lines, transformers, or capacitor banks<\/strong>;<\/li>\n\n\n\n
  • They may have switching-rod actuation (manual)<\/strong> or motorised<\/strong> operation, with or without locking mechanisms;<\/li>\n\n\n\n
  • They are highly visible, which is an operational advantage \u2014 the open position is easily identifiable with the naked eye.<\/li>\n<\/ul>\n\n\n\n
      \n
    • Use:<\/strong> Indoor panels or sheltered environments.<\/li>\n\n\n\n
    • Characteristics:<\/strong> Visible opening through a metal blade; simple, robust, and reliable.<\/li>\n\n\n\n
    • Application:<\/strong> Normally used in secondary circuits, low-voltage panels, or equipment with visually assisted operation.<\/li>\n<\/ul>\n\n\n\n

      2. Rotary Disconnect Switch<\/strong><\/h4>\n\n\n\n
        \n
      • Use:<\/strong> Sheltered or exposed installations, depending on the degree of protection.<\/li>\n\n\n\n
      • Characteristics:<\/strong> Rotational mechanism to open\/close the circuit; can be operated locally or remotely.<\/li>\n\n\n\n
      • Application:<\/strong> Medium-voltage panels, auxiliary circuits, and fast switching systems.<\/li>\n<\/ul>\n\n\n\n

        3. Pedestal \/ Pole-Mounted Switch (Outdoor Load Break Switch or Air Break Switch)<\/strong><\/h4>\n\n\n\n
          \n
        • Use:<\/strong> Field installation (pole or metallic structure).<\/li>\n\n\n\n
        • Characteristics:<\/strong> May include load-breaking capability; generally equipped with insulators and switching-rod or motorised operation.<\/li>\n\n\n\n
        • Application:<\/strong> Distribution branches, line switches, feeder isolation, and interconnections.<\/li>\n<\/ul>\n\n\n\n

          4. Motorised Switches with Supervision<\/strong><\/h4>\n\n\n\n
            \n
          • Use:<\/strong> Installations that require remote operation and integration with SCADA\/SAS systems.<\/li>\n\n\n\n
          • Characteristics:<\/strong> Electric actuators, position sensors, and communication with supervisory systems.<\/li>\n\n\n\n
          • Application:<\/strong> Automated substations, critical switching switches, and integration with protection logic and teleassistance.<\/li>\n<\/ul>\n\n\n\n

            The choice of the proper switch depends on factors such as voltage level, physical location, the need for load switching, supervision requirements, and access to the installation<\/strong>. In modern projects, it is recommended that all operationally critical switches be prepared for remote supervision and assisted operation<\/strong>, with position sensors and integration with CCTV systems or programmed logic.<\/p>\n\n\n\n

            Monitoring Requirement: What ANEEL Says<\/strong><\/h2>\n\n\n\n

            Monitoring disconnect switches in substations has stopped being a technical recommendation and has become a formal regulatory requirement established by ANEEL<\/strong>, especially since Normative Resolution No. 846\/2019<\/strong>, which governs the Distribution Procedures (PRODIST).<\/p>\n\n\n\n

            In Module 6<\/strong> of PRODIST, which addresses the operation of the distribution network<\/strong>, it is established that:<\/p>\n\n\n\n

            \n

            “Remote supervision of switching and protection equipment shall be provided, with a view to automated or remotely assisted operation, whenever technically feasible.”<\/em><\/p>\n<\/blockquote>\n\n\n\n

            This means that when designing or modernising substations, it is mandatory to provide remote supervision of switches<\/strong>, especially those responsible for isolating lines, branches, transformers, and critical feeders.<\/p>\n\n\n\n

            This supervision may be carried out through position sensors integrated with system logic, by direct automation via relay\/IED, or even through teleassistance systems with visual support through CCTV<\/strong>, in which switching is performed under the remote supervision of a technical operator.<\/p>\n\n\n\n

            In addition to meeting ANEEL requirements, this practice is aligned with international safe-operation standards, and is often required by utilities and distribution companies when approving projects from contractor partners.<\/p>\n\n\n\n

            Teleassistance: Remote Operation for Risk Mitigation<\/strong><\/h2>\n\n\n\n
            \"Monitoring
            Monitoring Disconnect Switches
            Collection – A3A Engenharia de Sistemas<\/figcaption><\/figure>\n\n\n\n

            Teleassistance<\/strong> in substations is a natural evolution of remote operation. It is a technical system that allows teams to visually monitor equipment position, validate switching operations in real time, and perform interventions with remote support<\/strong>, keeping the operator safe and the system under control.<\/p>\n\n\n\n

            When applied to the monitoring of disconnect switches<\/strong>, teleassistance makes it possible to:<\/p>\n\n\n\n

              \n
            • Visually verify switch position<\/strong> (open, closed);<\/li>\n\n\n\n
            • Monitor switching operations in real time<\/strong>, with remote supervision by the technical team;<\/li>\n\n\n\n
            • Record video of critical switching operations<\/strong>, with date and time stamps, for technical auditing and traceability purposes;<\/li>\n\n\n\n
            • Act preventively against operational failures<\/strong>, such as incomplete opening, mechanical obstruction, or insulation failures;<\/li>\n\n\n\n
            • Provide remote guidance to the local team<\/strong>, with visual support for the safe execution of procedures.<\/li>\n<\/ul>\n\n\n\n

              Why is this important?<\/h4>\n\n\n\n
                \n
              1. Reduced travel requirements<\/strong>
                Avoids sending technical teams to remote substations just to verify positions or carry out simple switching operations.<\/li>\n\n\n\n
              2. Improved operational safety<\/strong>
                Allows the operator to perform switching under supervision, reducing the risk of errors or accidents.<\/li>\n\n\n\n
              3. Faster response to events<\/strong>
                Minimises the time between the occurrence of a fault and decision-making, which is essential to ensure continuity of supply.<\/li>\n\n\n\n
              4. Technical and documentary compliance<\/strong>
                Switching-operation videos can be attached to reports, increasing technical reliability and system governance.<\/li>\n<\/ol>\n\n\n\n

                Teleassistance integrates directly with CCTV, telecommunications, access control, and supervisory systems<\/strong>, and is currently one of the main resources applied in automated substations or critical environments with unmanned operation.<\/p>\n\n\n\n

                Operational and Strategic Benefits<\/strong><\/h2>\n\n\n\n

                Implementing solutions that combine monitoring of disconnect switches in substations<\/strong> with teleassistance provides a series of concrete benefits, both at the operational and strategic levels, especially in projects with high responsibility for supply continuity and infrastructure safety.<\/p>\n\n\n\n

                Operational<\/strong><\/h4>\n\n\n\n