PGS(FLW) Series SF6 Insulated Load Break Switch — Full Voltage Range Type-Certified (12 kV to 40.5 kV)

For utilities and industrial operators managing medium-voltage distribution networks spanning multiple voltage levels, sourcing load break switches from a single manufacturer with consistent design philosophy and full type-test coverage across all required voltages simplifies procurement, spare parts management, and maintenance training.

This article presents the PGS(FLW) series SF6 insulated load break switches from Guoyuan Electric — a single product family available at 12 kV, 27 kV, and 40.5 kV — each backed by independent dielectric performance type test reports from XIHARI, China’s premier high-voltage apparatus research institute.

The Challenge: One Product Family Across Multiple Voltage Levels

Distribution networks rarely operate at a single voltage. A typical system may include:

• 12 kV (or 11 kV / 13.8 kV) — Urban distribution, industrial feeders
• 24–27 kV (or 22–33 kV) — Sub-transmission tie-lines, mining, large industrial complexes
• 38–40.5 kV (or 33–36 kV) — Substation outlet protection, renewable energy collection grids

Specifying different manufacturers for each voltage level introduces incompatible operating mechanisms, diverging spare parts inventories, and inconsistent maintenance procedures. A unified product family eliminates these inefficiencies.

PGS(FLW) Series — Three Models, One Proven Design Platform

The PGS(FLW) series shares a common architecture across all voltage classes:

Specification	PGS(FLW)-12/630-25	PGS(FLW)-27/630-25	PGS(FLW)-40.5/630-25
Rated Voltage (Ur)	12 kV	27 kV	40.5 kV
Rated Current (Ir)	630 A	630 A	630 A
Rated Frequency	50 Hz	50 Hz	50 Hz
Rated Short-Circuit Breaking Current	25 kA	25 kA	25 kA
Rated Short-Circuit Making Current	63 kA	63 kA	63 kA
Rated Short-Time Withstand (4 s)	25 kA	25 kA	25 kA
Rated Peak Withstand Current	63 kA	63 kA	63 kA
Mechanical Endurance Class	M2	M2	M2
Electrical Endurance Class	E2	E2	E2
Capacitive Switching Class	C2	C2	C2
SF6 Pressure @ 20°C (rated)	0.05 MPa	0.05 MPa	0.05 MPa
SF6 Min. Functional Pressure	0.04 MPa	0.04 MPa	0.04 MPa
Operating Sequence	O—0.3s—CO—180s—CO

Complete Type Test Certification Matrix

Each voltage class has been independently tested by XIHARI (Xi’an High Voltage Apparatus Research Institute Changzhou Co., Ltd.), a laboratory holding CNAS accreditation (L0223), ilac-MRA mutual recognition, and CMA certification (No. 220008343867).

Test Results Summary

Test Item	Standard	12 kV Result	27 kV Result	40.5 kV Result
Power-Frequency Withstand (phase-to-earth, dry/wet)	GB/T 1984-2014 §6.2 IEC 62271-100 §7.2	42/42 kV — Pass	65/65 kV — Pass	95/95 kV — Pass
Power-Frequency Withstand (across open device)	Same	42 kV — Pass	65 kV — Pass	95 kV — Pass
Lightning Impulse (phase-to-earth)	Same	75 kV — Pass	125 kV — Pass	185 kV — Pass
Lightning Impulse (across open device)	Same	75 kV — Pass	125 kV — Pass	185 kV — Pass
Auxiliary Circuit Dielectric	GB/T 1984-2014 §6.2.10	2000 V/1min — Pass	2000 V/1min — Pass	2000 V/1min — Pass
Report Number	—	235477	235478	235479
Approval Date	—	2023-07-06	2023-07-07	2023-07-06

Key Technical Advantages Validated by Independent Testing

1. Dual-Standard Compliance (GB + IEC)

The 27 kV model was explicitly tested to IEC 62271-100:2021 — the current international baseline for high-voltage switchgear. This means projects specifying IEC standards (common in Africa, Middle East, Southeast Asia, and Latin America) can reference this report directly in tender submissions.

2. Conservative Design Margins

All three models’ withstand voltage levels meet or exceed the minimum requirements of their respective voltage classes per IEC 60694 / GB/T 311.1 coordination tables. The 185 kV lightning impulse rating for the 40.5 kV model, for instance, provides substantial margin above the typical 170 kV minimum for Um = 40.5 kV systems.

3. Extended Endurance Ratings (M2 / E2 / C2)

The type-verified M2 mechanical endurance (10,000+ operations), E2 electrical endurance (extended load-switching capability), and C2 capacitive switching (restrike-free cable-charging current interruption) classes reduce replacement frequency and total cost of ownership.

4. Hermetically Sealed SF6 System

The stainless-steel welded tank design ensures zero SF6 leakage over the equipment lifetime, eliminating the need for gas refilling or pressure monitoring maintenance. The type-confirmed pressure range (0.04–0.05 MPa absolute at 20°C) guarantees reliable arc-quenching performance throughout the service life.

Selecting the Right Model for Your Application

Application Scenario	Recommended Model	Typical Markets
Urban/rural distribution networks (MV primary)	PGS(FLW)-12/630-25	SE Asia, Africa, LatAm (11–15 kV systems)
Sub-transmission, mining, heavy industry	PGS(FLW)-27/630-25	Mining (24 kV), industrial (22–33 kV)
Substation outlet, wind/solar collection	PGS(FLW)-40.5/630-25	Grid-tied renewables (33–40.5 kV)