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High-Voltage Equipment
Types of Control Relays for Tap Changers
The product presented here is the standard version. Modifications are possible and can be easily requested from us. We will be happy to provide consultation and work with you to find the optimal solution.
TYPE 12
| Type of Connection | Nominal Pipe Diameter (mm) | Flange Dimensions (mm) | Device Dimensions (mm) | Weight Without Packaging (kg) | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
| d1 | d2 | d3 | d4 | d5 | f | l | h1 | h2 | ||
| Flange 4 holes |
25 | 115 | 85 | 68 | 14 | 16 | 200 | 195 | 62 | 4.0 |
Control Relays for Tap Changers
Control relays for tap changers, also known as protection relays for tap changers or oil flow relays, are control devices used in tap changers filled with liquid oil dielectric and equipped with an expansion tank. Their purpose is to protect the tap changer and the transformer from damage. The control relay responds to excessively intense oil flow in the direction of the expansion tank and sends a signal that can be used to disconnect the tap changer and the transformer. Control relays for tap changers are used both in outdoor installations and indoor environments.
The control relays supplied by AFC stand out primarily for their ease of maintenance, high reliability, and exceptionally long service life.
Highly qualified technical staff and the experienced workforce of the manufacturers ensure the production of devices with high precision and excellent quality. The mechanical processing of housings is carried out on modern multi-operation CNC machines. Final testing includes a check of all functions of each individual device using specialized test equipment.
The experience gained in this specialized field, conscientiously applied in practice, provides a reliable foundation for the high quality of the products. Numerous references from well-known tap changer and transformer manufacturers, as well as other users, confirm the high standard of these devices.
Housing Assembly
The housing is made of cast aluminum alloy resistant to weather conditions and features a protective paint coating. For visual monitoring of the switching system’s operation, the housing includes inspection windows located opposite each other, protected by covers (1) that can be lifted upward. The control relay responds to excessively intense oil flow in the direction of the expansion tank and sends a signal that can be used to disconnect the tap changer and the transformer. Control relays for tap changers are used in both outdoor installations and indoor environments.
Cover Assembly
The cover is made of cast aluminum alloy resistant to weather conditions and features a protective paint coating. At the top of the cover, there is a terminal box (1). In front of it is a test and reset button, covered with a cap nut (2) and a threaded plug (3) or, optionally, an air release valve (see section 9 “Explanation of Code 97”).
Additionally, a nameplate (4) with instructions for operating the test and reset button is mounted here. Inside the terminal box, there is a grounding contact (5) and electrical terminals (6) installed in the bottom of the cover. The terminal box is sealed with an aluminum cap (7), which provides protection against contact and contamination. On the inner side of the cap, the designation and terminal layout diagram (8) are indicated.
The connecting cable is inserted through a threaded cable gland (9).
The control relay responds to excessively intense oil flow in the direction of the expansion tank and sends a signal that can be used to disconnect the tap changer and the transformer.
Control relays for tap changers are used in both outdoor installations and indoor environments.
Control relays are installed in the pipeline between the tap changer and the expansion tank, preferably as close as possible to the tap changer head. During normal operation of the tap changer, gases are generated and accumulate in the gas chamber of the control relay. Once the gas chamber reaches its capacity, any further gas formation causes it to flow toward the expansion tank.
Malfunction: As a result of an incident, an oil flow occurs in the direction of the expansion tank.
Response: The intense flow reaches a valve shutter located in the liquid flow. If the flow speed exceeds the actuation threshold of the valve shutter, it begins to move in the direction of the flow.
As a result of this movement, a switching contact is activated, which leads to the shutdown of the tap changer and the transformer.
| Parameter | Value / Data | Remarks |
|---|---|---|
| Voltage | AC 5 V – max. 250 V DC 5 V – max. 250 V |
Consider the maximum connected power |
| Current | AC 0.01 A – max. 6 A DC 0.01 A – max. 6 A |
Cos φ > 0.5 L/R < 40 ms, consider the maximum connected power |
| Connected Power | AC max. 1500 VA DC max. 1250 W |
- |
| Dielectric Strength | AC 2500 V AC 2000 V (opening) AC 1000 V (switch) |
Between circuit and ground, between open contacts |
| Temperature Range: - Ambient temperature |
-40 °C to +55 °C -40 °F to +131 °F |
Climatic test according to Others on request |
| Temperature Range: - Operating range - Insulating liquid temperature |
-40 °C to +115 °C -40 °F to +239 °F Up to +135 °C – option 211 |
|
| Temperature Range: - Operating range - Insulating liquid viscosity |
1 mm²/s to 1100 mm²/s | |
| Insulating Liquid | Mineral oil | - |
| Vibration Resistance | Vibration: 2.20 Hz, 1 g Shock: 10 g, 11 ms |
- |
| Compressive Strength Limit | 0.25 MPa | - |
| Vacuum Strength | < 2.5 kPa | - |
| Magnetic Field Immunity | 25 mT | Magnetic balance in any direction and polarity |
| Switching Systems | 1 Magnetically controlled contact, held by magnet < 0.1 s |
- |
| Cable Gland | M20 × 1.5; M25 × 1.5 | Others on request |
| Nominal Installation Position | 2° to 4° | With upward slope towards the expansion tank |
| Protection Class | IP 56 | Others on request |
| Housing Coating | Two-component textured paint |
Polyurethane-based |
Comprehensive Approach
LLC "Autoformula Center" guarantees the reliability and durability of electrical equipment for strategically important energy enterprises.
Stages of Cooperation with the Client
5
Needs Analysis
We study the customer’s requirements.
We analyze technical parameters, operating conditions, and regulatory requirements to provide the most suitable solution.
Design
We agree on technical specifications.
We work with design organizations and manufacturers to adapt the equipment to specific operating conditions.
Supply
We ensure quality and deadlines.
We organize logistics, guarantee compliance of the equipment with technical requirements, and ensure timely delivery.
Installation and Commissioning
We support the installation process.
We integrate the equipment into existing systems and coordinate commissioning to ensure uninterrupted operation.
Service and Support
We ensure reliable operation.
We provide after-sales service, supply spare parts, and offer consultation on equipment operation.