This article written by China automatic recloser manufacturer, explains the function and great value of the 33KV automatic reclosing system.
Auto recloser 33kV is an intelligent switchgear installed on 33kV medium-voltage distribution lines.
The auto recloser 33KV integrates detection, protection, and control functions. Its core function is to automatically cut off the current when a line fault occurs and attempt to reclose the circuit after a preset delay, thus distinguishing between transient faults (such as lightning strikes or bird strikes) and permanent faults (such as broken wires or equipment damage).
Real-time monitoring of line current, voltage, and other parameters. Upon detecting a short circuit or ground fault, the auto recloser 33KV system immediately initiates a tripping operation to isolate the faulty section and prevent escalation.
Initial Reclosing: The system attempts to reclose within tens of milliseconds to several seconds after a fault occurs. If the transient fault has disappeared (e.g., insulation recovery after a lightning flashover), the normal power supply is restored.
Multiple Attempts: Typically, a preset reclosing sequence of 1–3 attempts is used (e.g., “tripping → delayed reclosing → tripping again → delayed reclosing again”). If the fault persists, it is considered a permanent fault, and the system remains in the tripped state, blocking the closing process.
Programmable Settings: Auto recloser 33KV supports adjustment of parameters such as delay time, number of reclosing attempts, and current setting to adapt to different line characteristics.
As a crucial component of the distribution network protection system, the 33kV automatic reclosing system achieves selective fault isolation through precise time-current differential coordination with equipment such as substation outgoing circuit breakers, downstream sectionalizing switches, and fuses.
When a line fault occurs, the upstream reclosing device closest to the fault point will operate before the substation outgoing circuit breaker, disconnecting the faulty section in the shortest possible time. If the fault persists, the protection signal will be transmitted upstream according to a preset delay, ensuring that the power outage is strictly limited to the minimum necessary section.
This “local first, upstream second” collaborative logic avoids the entire feeder from being shut down due to a single fault and significantly shortens the recovery time of non-faulty areas, forming the core technological foundation for building a highly reliable self-healing distribution network.
Modern automatic reclosing systems typically have remote monitoring interfaces (such as SCADA and IoT), supporting “four remote” functions (telemetry, remote signaling, remote control, and remote adjustment) for centralized scheduling and management.
Built-in event loggers store data such as fault current and action time, providing maintenance personnel with clear evidence for fault analysis.
Significantly Improves Power Supply Reliability
Statistics show that over 80% of faults in medium-voltage distribution networks are transient. Automatic reclosing can automatically restore power supply during these faults, avoiding unnecessary prolonged power outages and increasing power availability to over 99%.
Reduces Operation and Maintenance Costs and Manual Intervention
Automatic fault handling reduces the need for inspections and on-site operations, especially beneficial in remote or terrain-challenged areas.
Protects Grid Equipment and Extends Lifespan
Rapidly isolates faults, mitigating the impact of fault currents on transformers, cables, and other equipment, reducing the risk of equipment damage.
Supports Distribution Network Automation and Intelligence
It is a key device for building self-healing grids, providing flexible and reliable control nodes for distributed energy access and microgrid operation.
Optimizes Grid Operation Economy
Reduces power outage losses, increases electricity sales, and simultaneously delays investment in line upgrades to enhance reliability.
The price of 33kV auto recloser depends on several factors, including technical specifications, brand and country of origin, functional modules, operating environment, and procurement channel.
Technical specifications include: rated current, short-circuit breaking capacity, operating mechanism (spring/permanent magnet), and the level of intelligence of the control unit.
Functional modules include: whether it integrates an FTU, a communication module (fiber optic/wireless), battery management, and advanced protection functions.
Operating environment includes: outdoor pole-mounted vs. cabinet-type, pollution resistance rating, and climate adaptability (extreme cold/high temperature).
Procurement channels include: bulk purchases for projects, distributor distribution, and after-sales service and training coverage.
Important Note: When choosing 33kV auto recloser, the total lifecycle cost should be considered, not just the purchase price. Reliability, localized technical support, and long-term spare parts supply are more critical.
What voltage are auto reclosers used at?
Auto reclosers are used across a wide range of distribution voltages, most commonly from 11kV (or 10kV) up to 38kV (or 34.5kV), covering the primary medium-voltage tiers of power distribution networks.
Where Are 33kV Auto Reclosers Used?
33kV auto reclosers are typically deployed on medium-voltage overhead feeders radiating from primary substations, commonly found in suburban areas, rural and semi-rural landscapes, industrial parks, and as interconnection points for renewable energy sources like small wind or solar farms.
How to Choose the Right 33kV Auto Recloser?
Choosing the right unit requires evaluating key specifications against your application: the rated current and short-circuit breaking capacity must match your grid’s fault levels, the protection and control functions should align with your automation strategy, and the mechanical design and enclosure must be rated for the local environment and climate.
Is a 33kV recloser suitable for urban applications?
Yes, but selectively. In dense urban networks with predominantly underground cable systems (where faults are often permanent), reclosers are less common. However, they are well-suited for urban overhead lines, ring-main systems for sectionalizing, or at the feeders supplying outlying or elevated urban-suburban transition areas.
What mechanical design features matter for harsh U.S. climates?
For harsh U.S. climates, key features include a sealed, corrosion-resistant stainless steel or hot-dip galvanized enclosure (IP67 rating or higher), a wide operational temperature range (e.g., -40°C to +65°C), internal thermostatically controlled heaters to prevent condensation, and ruggedized, weatherproof bushings and operating mechanisms designed for heavy ice loading, high winds, and salt-laden or desert environments.
For power supply companies, investing in a reliable auto recloser 33KV means less power outage time, lower operating costs, and higher customer satisfaction. The value of this investment far exceeds the price of the equipment itself.
Now that you understand the powerful functions and core value of 33kV automatic recloser, are you looking for a highly reliable intelligent solution for your power distribution network?
GOTO Electric is an auto recloser manufacturer in China, specializing in providing highly reliable and intelligent automatic reclosing solutions for global power distribution networks.
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