Product Introduction
The LW36-145/3150-40 self-powered SF6 circuit breaker is an outdoor type product, suitable for use in power grids with a maximum voltage of 145 kV, operating at 50 Hz and altitudes not exceeding 3000 meters, with an ambient temperature no lower than -40°C, and environmental pollution levels not exceeding level IV.
It is designed to disconnect rated current, fault current, or switch lines, achieving control and protection of the power system. It can also be used as a link circuit breaker.
This product uses SF6 gas as the arc-extinguishing and insulating medium, and incorporates the most advanced self-powered arc-extinguishing technology. It is equipped with a new type of spring operating mechanism, offering features such as long electrical life, low operating force, low noise, and high reliability.
Its simple structure, compact size, and long maintenance intervals make it an ideal choice for high-altitude regions or 132 kV power systems. It can replace similar imported products.
Structural Features
The circuit breaker adopts a three-phase porcelain column-type single-break structure, with a single spring operating mechanism shared by the three phases. It is centrally arranged with three-phase interlocking, giving it an innovative and refined appearance.
The circuit breaker uses SF6 gas as both the insulating and arc-extinguishing medium. During operation, the three poles of the breaker are connected via SF6 gas, and a pointer-type density relay is used to monitor its pressure and density progress. Due to the use of self-powered arc-extinguishing technology and optimized design in the breaker’s motion system, the mechanical efficiency is effectively improved, minimizing the operating force. The breaking performance is excellent, and the electrical life is long.
The installation base and support frame are made of high-quality steel plates, formed by overall bending. The surface is treated with hot-dip galvanizing, and all exposed fasteners are made from high-strength materials, either hot-dip galvanized or made of stainless steel. The mechanism box casing is made of stainless steel, ensuring excellent corrosion resistance, high mechanical reliability, and the ability to withstand frequent operations.
Main Technical Parameters of Circuit Breaker
| No. | Parameter Name | Unit | Value |
| 1 | Rated voltage | kV | LW36-126KV |
| 2 | Insulation level | kV | See Table 2 |
| 3 | Rated frequency | Hz | 50 |
| 4 | Rated current | A | 3150 |
| 5 | Rated short-circuit breaking current | kA | 40 |
| 6 | Rated short-time withstand current | kA | 40 |
| 7 | Rated peak withstand current | kA | 100 |
| 8 | Rated short-circuit duration | s | 3 |
| 9 | Rated short-circuit making current (peak) | kA | 100 |
| 10 | Near-zone fault breaking current | kA | 36/30 |
| 11 | Rated line charging breaking current | A | 31.5 |
| 12 | Rated out-of-step breaking current | kA | 10 |
| 13 | Cumulative short-circuit breaking operations | times | 20 |
| 14 | First pole-to-clear factor | – | 1.5 |
| 15 | SF6 gas pressure (20°C) | MPa | 0.5 |
| 16 | Rated voltage of control/auxiliary circuits | – | DC220V / DC110V* |
| 17 | Rated operating sequence | – | O-0.3s-CO-180s-CO |
| 18 | Mechanical characteristics | μΩ | See Table 5 |
| 19 | Rated main circuit resistance | μΩ | ≤55 |
| 20 | Mechanical endurance | times | 10000 |
| 21 | Terminal static pull force | N | Horizontal longitudinal：1250 |
| Horizontal lateral: 750 | |||
| Vertical direction: 1000 | |||
| 22 | SF6 gas annual leakage rate | % | ≤1 |
| 23 | SF6 gas moisture content (V/V) | ppm | ≤150±4 |
| 24 | Contact travel | mm | 150±4 |
| 25 | Contact closing travel | mm | 25+3 |
