Pagkumpara sa mga 10kV Pole-Mounted Switches (Isolator Load Switch Circuit Breaker ug Fuse)

2yrs + staff 1000+m² US$300,000,000+ China

Ano ang Pole-Mounted Switch?
Isa itong mekanikal na switching device na inilalapat sa mga outdoor utility poles sa 10kV overhead distribution lines, ginagamit sa suburban at rural distribution networks. Ito ay disenyo upang sirain, isara, at i-carry ang line load currents at fault currents.
Ang pole-mounted switches sa pangkalahatan ay binubuo ng switch body na may sensors + FTU (Feeder Terminal Unit). Ang mga switch na pinag-uusapan sa ibaba ay kasama sa kategorya ng pole-mounted disconnectors (isolators).

2. Klasipikasyon ng Pole-Mounted Switches
Ang pole-mounted switches maaaring ikasakatuparan mula sa maraming dimensyon. Ang core na paraan ng pagkakasunud-sunod at katangian ay sumusunod:

Ayon sa Interrupting Capacity:

a. Pole-Mounted Disconnector (Isolator): Wala ring kakayahang apawin ang arc; hindi maaaring isara o sirain ang normal na load current. May visible break (isolation gap). Ang core purpose nito ay upang hiwalayin ang mga linya upang mapanatili ang kaligtasan sa panahon ng maintenance.
b. Pole-Mounted Load Switch: May basic na kakayahang apawin ang arc; maaaring isara, carry, at sirain ang normal na load current (≤630A). Maaaring carry pero hindi maaaring sirain ang fault current.
c. Pole-Mounted Circuit Breaker: Malakas na kakayahang apawin ang arc; maaaring isara, carry, at sirain ang normal na load current (≤630A) at fault current (≥20kA).
d. Pole-Mounted Fuse (Drop-Out Fuse): Core function ay upang sirain ang short-circuit current; ginagamit para sa protection ng line short-circuit.

3. Pole-Mounted Disconnector (Isolator)
Tinatawag din itong "isolating knife switch," ito ay isang kontrol device na walang arc-extinguishing mechanism. Ang core function nito ay upang hiwalayin ang power supply upang mapanatili ang safe maintenance ng iba pang electrical equipment. Hindi pinapayagan ang operasyon under load (ito lamang maaaring gawin/sirain ang low-power circuits sa ilang kondisyong espesyal). Isa ito sa pinaka-widely used at madalas na operasyon na mga device sa high-voltage switching.

3.1 Core Uses

Paghiwalay ng line equipment para sa maintenance, fault finding, cable testing, at reconfiguring operational modes.
Kapag binuksan, ito ay hiwalayin ang equipment na nasa maintenance mula sa live line, nagbibigay ng reliable insulation gap at nagbibigay ng "visible, clear break indication" upang mapanatili ang seguridad ng mga tao.
Nagsisilbing demarcation switch sa pagitan ng overhead lines at user property, o sa pagitan ng cable lines at overhead lines.
Inilalapat sa isa o parehong gilid ng tie load switch upang mapadali ang fault finding, cable testing, at maintenance/replacement ng tie load switch.

3.2 Key Characteristics

Advantages: Mababang cost, simple structure, matatag.
Limitations: Hindi maaaring mag-operate under rated load/heavy load; hindi maaaring sirain o gawin ang load current at short-circuit current.
Operating Procedure: Para sa energizing: "Unawain muna ang isolator, pagkatapos unawain ang circuit breaker/load switch." Para sa de-energizing: "Bukasin muna ang circuit breaker/load switch, pagkatapos buksan ang isolator."
Special Permissible Conditions: Maaaring gawin/sirain ang magnetizing current ng no-load transformers (≤2A) at ang capacitive current ng no-load lines (≤5A).
Technical Parameters: Karaniwan, peak withstand current (dynamic stability) ≤40kA (dapat ma-verify sa panahon ng selection). Ang mechanical operating life ay humigit-kumulang 2000 cycles.

4. Pole-Mounted Load Switch
Nakakabit ng simple na arc-extinguishing device, maaari itong gawin at sirain ang circuits under load. Maaari itong sirain ang ilang load currents at overload currents ngunit hindi maaaring sirain ang short-circuit currents. Kailangan itong gamitin sa serye kasama ang high-voltage fuse (na cuts off ang short-circuit current). Ang functionality nito ay nasa gitna ng isang isolator at circuit breaker. Ang core uses nito ay line sectioning at fault isolation.

4.1 Common Types and Characteristics

Uri	Arc-Extinguishing Principle	Advantages	Applicable Scenarios
Gas-Production Load Switch	Solid gas-producing material generates gas under arc action, creating gas blast to extinguish arc.	Simple structure, low cost.	Scenarios with low operating frequency requirements.
Vacuum Load Switch	Vacuum arc extinction, often combined with SF₆ insulation.	Long life, maintenance-free, mechanical life ≥10,000 cycles.	Scenarios requiring frequent operation.
SF₆ Load Switch	SF₆ arc extinction + SF₆ insulation.	Excellent arc extinction/insulation performance, maintenance-free.	Scenarios requiring high reliability.

4.2 Mainstream Product Structural Features

Vacuum Load Switch: Three-phase common tank type, equipped with VSP5 electromagnetic/spring operating mechanism. Can have built-in current transformers (CTs) and isolation gaps. Supports cable/terminal outgoing lines. Can be mounted hanging or sitting.
SF₆ Load Switch: Three-phase common tank type. Can have built-in current transformers (CTs). Optional external isolation device. Supports cable/terminal outgoing lines. Can be mounted hanging or sitting.

5. Pole-Mounted Circuit Breaker
Isa itong switching device na may complete na arc-extinguishing capability. Maaaring isara, carry, at sirain ang normal circuit current, at maaaring carry at sirain ang abnormal circuit currents (overload, short-circuit) sa loob ng tiyak na panahon. Ang function nito ay katumbas ng combination ng "fused switch + over/under thermal relay." Ang pole-mounted circuit breakers ay karaniwang tinatawag na "reclosers" o "auto-reclosers." Inilalapat sa poles, ito ang core equipment para sa protection at control sa distribution network sections.

5.1 Core Uses

Sectionalizing, switching, control, at protection ng mga segment ng distribution line; capable ng active interruption at closing ng short-circuit currents.
Normal na ginagamit upang buksan/sarado ang mga linya; sa panahon ng mga fault, automatic o manual (sa pamamagitan ng relay protection devices) ang switching out ng faulty lines.
Inilalapat sa responsibility demarcation points sa 10kV overhead lines; maaaring automatically clear single-phase earth faults at isolate short-circuit faults. Isang core device para sa distribution automation upgrades.

5.2 Classification and Mainstream Products
Classified by arc-extinguishing medium: Oil circuit breaker (largely obsolete), SF₆ circuit breaker, Vacuum circuit breaker (current mainstream).
Outdoor AC high-voltage intelligent vacuum circuit breakers are currently the preferred choice for distribution lines, featuring:

Functions: Fault detection, protection control, communication capabilities.
Operation Methods: Manual, electric, remote control, host computer remote operation.
Composition: Body + operating mechanism + controller (may include built-in isolator).
Optional Components: CT (Protection Current Transformer), ZCT (Zero-Sequence Current Transformer), PT (Voltage Transformer).

5.3 Vacuum Circuit Breaker Subtypes

SF₆ Insulated Vacuum Circuit Breaker: Vacuum arc extinction + SF₆ insulation. Three-phase common tank. Spring operating mechanism. Can have built-in CTs. Optional external isolation device. Hanging or sitting mounting.
Air Insulated Vacuum Circuit Breaker: Vacuum arc extinction + air insulation. Three-phase solid-pole type. Spring or permanent magnet operating mechanism. External CTs. Optional external isolation device. Sitting mounting.

6. Drop-Out Fuse
Karaniwang tinatawag na "fuse cutout," ito ang pinaka-commonly used na short-circuit protection switch para sa branch lines at distribution transformers sa 10kV distribution networks. Ito ay ekonomiko, madali manipulan, at suitable para sa outdoor environments. Malawakang ginagamit para sa protection at switching operations sa 10kV lines at primary side ng distribution transformers.

6.1 Core Uses

Inilalapat sa 10kV distribution branch lines: Limits the scope of power outages. Provides an isolator function due to its visible break, creating a safe environment for maintenance.
Inilalapat para sa distribution transformers: Serves as the main protection for transformers, safeguarding them against overload and short-circuit impacts.

6.2 Installation and Structure

Installation Location: Can be installed on the source side of a load switch (preferred when fuses don't need frequent replacement, allows the load switch to isolate voltage) or on the load side.
Core Components: Insulator, lower support base, lower moving contact, lower fixed contact, mounting plate, upper fixed contact, "duckbill" contact, upper moving contact, fuse tube.

7. Core Differences Between Pole-Mounted Switches
The key differences between various pole-mounted switches lie in three main dimensions: arc-extinguishing capability, types of interruptible current, and protection function. A detailed comparison is below:

Switch Type	Arc-Extinguishing Device	Interruptible Current Types	Carry Current Types	Protection Coordination Requirement	Core Purpose
Disconnector (Isolator)	None	Only system no-load current	Working current, short-circuit current (short time)	No protection coordination needed, used solely for isolation.	Safety isolation for maintenance, visible break.
Load Switch	Simple	Normal load current, overload current	Working current, short-circuit current (short time)	Requires series connection with fuse; fuse interrupts short-circuit current.	Line sectioning, normal load switching.
Circuit Breaker	Full	Normal load current, overload current, short-circuit current	Working current, short-circuit current (for specified time)	Requires coordination with relay protection device; protection issues trip command.	Fault clearance, comprehensive line protection.
Drop-Out Fuse	Simple	Short-circuit current, overload current	Working current (normal conditions)	Used alone, provides direct short-circuit/overload protection.	Short-circuit protection for branch lines & transformers.

Summary

Disconnector (Isolator): Only breaks no-load current; provides a "visible break point" for safe maintenance.
Load Switch: Breaks normal load current, not fault current; requires a fuse for fault protection.
Circuit Breaker: Breaks both normal load and fault currents; requires relay protection coordination; core device for distribution network protection.
Drop-Out Fuse: Specifically breaks short-circuit/overload currents; provides low-cost protection for branch lines and transformers.