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ASNA busbar PT unit

As an 

advanced power distribution switchgear supplier, HM Power 

designs the ASNA busbar PT unit (symbol: PT) to sample busbar voltage via voltage transformers, output secondary voltage signals for metering and protective relays, and also supply auxiliary power to secondary circuits.


Users may adopt single-phase, V-V or star-delta wiring schemes for different projects. For PTs with star-delta wiring, a harmonic suppressor must be fitted to safeguard PT neutral insulation against damage from system resonance.

ASNA busbar PT unit

The ASNA busbar PT unit(symbol:PT) samples busbar voltage via voltage transformers, outputs secondary voltage signals for metering and protective relays, and can also supply auxiliary power to secondary circuits. Users may adopt single-phase, V-V or star-delta wiring schemes for different projects. For PTs with star-delta wiring, a harmonic suppressor must be fitted to safeguard PT neutral insulation against damage from system resonance.

Introduction

Core functions

Measuring Voltage Supply - Output: AC 100 V measuring voltage

Secondary Power Supply -Power output: AC 220 V / AC 230 V

 Easy Maintenance: The unit is equipped with a three-position disconnector. When the PT malfunctions, the disconnector can be disconnected for maintenance while the busbar remains energized.

Parameter List

Parameter list of 24kV busbar PT Unit
Parameter list of 12kV busbar PT Unit
Name Unit Parameter
Rated voltage(Ur) kV 24
Rated frequency(fr) Hz 50
Rated current(lr) A 630 1250
Rated Short-duration power-frequency withstand voltage(Ud) Common value kV 50
Across the isolating distance 60
Rated Lightning impulse withstand voltage(up) Common value kV 125
Across the isolating distance 145
Rated short-time withstand current(lk) kA 20 25
Rated short-time duration(tk) s 4
Rated peak withstand current(lp) kA 50 63
Rated short-circuit making current(lma) Three-position disconnector kA 50 63
Mechanical endurance Three-position disconnector time 3000
Electrical endurance Earthing Switch class E2
Degree of protection by enclosure   IP4X
Degree of protection by Fully Sealed tank   IP65
Dimension Low voltage chamber not included W(mm) 720
D(mm) 850
H(mm) 1890 1940

Busbar PT Unit Structure 

Name Unit Parameter
Rated voltage(Ur) kV 12
Rated frequency(fr) Hz 50
Rated continuous current(lr) A 630 1250
Rated short-duration power-frequency withstand voltage(Ud) Common value kV 28
Across the isolating distance 32
Rated lightning impulse withstand voltage(Up) Common value kV 75
Across the isolating distance 85
Rated short-time withstand current(Ik) kA 20 /25 20/25/31.5
Rated short-time of short-circuit(tk) s 4
Rated peak withstand current(Ip) kA 50 / 63 50/63/80
Rated short-circuit making current(Ima) Three-position disconnector kA 50 / 63 50/63/80
Mechanical endurance Three-position disconnector time 3000
Electrical endurance Earthing Switch class E2
Degree of protection by enclosure   IP 4X
Degree of protection by fully sealed tank   IP 65
Dimensions
Low voltage chamber not included
W(mm) 600
D(mm) 800 900
H(mm) 1640 1810

Application

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Italy PCS Energy Storage Integrated Unit Power Distribution Project
Italy has witnessed rapid growth in installed capacity of wind and solar new energy, with steadily rising demand for energy storage on both grid-side and commercial & industrial sides. By charging and discharging to implement peak shaving and valley filling, energy storage systems effectively smooth grid fluctuations and reduce power consumption costs. As a critical component for grid connection, the medium-voltage switchgear supporting energy storage power stations is subject to growing attention on environmental compliance. Relevant EU greenhouse gas control regulations impose mandatory constraints on equipment selection. The EU F-Gas Regulation (EU) 2024/573 clearly stipulates that SF₆ greenhouse gas shall be prohibited for new medium-voltage switchgear with rated voltage ≤24kV starting from 1 January 2026.
Power Distribution Project of Tanzania Sapphire Float Glass Industrial Park
The Tanzania Sapphire Float Glass Industrial Park is a benchmark project under China’s Belt and Road Initiative. The glass manufacturing process imposes extremely stringent requirements on power supply continuity, power quality and voltage stability. Meanwhile, the park features complex operating conditions including high temperature, high humidity, dust and tin fog corrosion, which pose severe challenges to the corrosion resistance and long-term operational reliability of power distribution equipment.
Smart City Distribution Project in Stockholm, Sweden
Stockholm, Sweden, is a benchmark for smart city and green low-carbon urban development in Northern Europe. It was awarded the world’s first "European Green Capital" title in 2010. As a key supporting initiative for the grid intelligence and urban low-carbon transition of Stockholm, this smart city power distribution project comprehensively improves the stability and environmental performance of urban public power supply and serves as an important pillar for long-term sustainable development.
Tesla Supercharger Station Power Distribution Project, Sweden
In 2014, the first batch of Tesla Superchargers in Västerås, Sweden, supporting this project was completed and put into operation. It serves as a highly representative energy replenishment infrastructure for new energy vehicles in Northern Europe. As a high-power dynamic electrical load scenario, the supercharger station imposes stringent requirements on the 10kV distribution system in terms of power supply reliability, equipment stability, fault handling capability and low-carbon compliance.
Power Distribution Project of Hainan Wenchang Space Launch Site
The commercial Wenchang Space Launch Site is located on the coast of Hainan, featuring year-round high humidity and salt spray. Its core power distribution room supports uninterrupted critical services including launch telemetry & control, command communication and data computation. It imposes aerospace-grade stringent requirements far exceeding ordinary industrial standards on the safety level of the power distribution system, power supply continuity, environmental weather resistance and long-period maintenance-free performance.
Haikou Meilan International Airport Phase II Expansion · ATC Station Room Renovation Project
As the core aviation hub of the Hainan Free Trade Port, Haikou Meilan International Airport undertakes key functions including passenger and cargo transportation as well as air traffic control (ATC) navigation support. The ATC station room renovation required an upgrade of the power distribution system under non-stop flight and uninterrupted ATC service conditions. The project demands absolutely continuous and secure power supply, while the equipment must adapt to on-site conditions featuring densely arranged devices and complex electromagnetic environments.
Tencent Data Center Power Distribution Project, Guizhou
Tencent Data Center in Guizhou is China’s first large-scale cave-type data center, undertaking core services including data storage and AI training. Power outages may result in data loss and computing capacity loss, so extremely high reliability requirements are imposed on power supply. Its unique geographic location also raises stringent requirements for anti-condensation performance and maintenance-free operation.
Qualification

Certification And Qualification

Questions and answered

1
Q: What are the differences among single-phase connection, V-V connection and star-delta connection?
A: A single-phase connection can only sample one line voltage. The V-V connection is capable of sampling three line voltages. The star-delta connection can sample three line voltages, three phase voltages and zero-sequence voltage.
2
Q: When does a harmonic suppressor need to be installed?
A: PTs adopting star-delta wiring require a harmonic suppressor. This type of PT has a neutral point; the suppressor prevents system resonance from damaging the insulation at the PT neutral point. The other two connection types do not feature neutral points and thus require no suppressor.
3
Q: How are the busbars connected to the PTs?
A: The busbars are connected to the PTs via replaceable fuses.
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No matter which stage your project is at, our professional team of engineers can provide you with full-process professional support from product selection, solution design, factory visits to delivery and maintenance.

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+86 18138383310
email
sales@hmpower-global.com

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