Tag: power

DC Power(R)

Posted on by lechuck park

Data Center DC Power System Comprehensive Overview

This diagram illustrates the complete DC (Direct Current) power supply system for a data center infrastructure.

1. Core Components

① Power Source

  • 15.4 KV High Voltage AC Power
  • Received from utility grid
  • Efficient long-distance transmission (Efficient Delivery)
  • High voltage warning indicator (High Warning)

② Primary Transformer

  • Voltage conversion: 15.4 KV → 6.6 KV
  • Function: Steps down high voltage to medium voltage
  • Transformation method: Voltage Step-down
  • Adjusts voltage for internal data center distribution

③ Backup Power #1 – Generator System (Long-Time Backup)

  • Configuration: Diesel generator + Fuel tank
  • Characteristic: Long-duration backup capability
  • Purpose: Continuous power supply during main power outage
  • Advantage: Unlimited operation as long as fuel is supplied

④ Secondary Transformer

  • Voltage conversion: 6.6 KV → 380 V
  • Function: Steps down medium voltage to low voltage
  • Transformation method: Voltage Step-down
  • Provides appropriate voltage for UPS and final loads

⑤ Backup Power #2 – UPS System (Short-Time Backup)

  • Configuration: UPS + Battery
  • Characteristic: Short-duration instantaneous backup
  • Purpose: Ensures uninterrupted power during main-to-generator transition
  • Role: Supplies power during generator startup time (10-30 seconds)

⑥ Final Load (Power Use)

  • Output voltage: 220 V AC or 48 V DC
  • Target: Servers, network equipment, storage systems
  • Feature: Stable IT infrastructure operation with DC power

2. Voltage Conversion Flow

15.4 KV (AC)  →  6.6 KV (AC)  →  380 V (AC)  →  48 V (DC) / 220 V
  [Reception]   [Primary TX]   [Secondary TX]   [Final Conversion]

3. Redundant Backup Architecture

Two-Tier Backup System

Main Power (15.4 KV) ─────┐
                          ├──→ Transform ──→ Load
Generator (Long-term) ────┘
         ↓
    UPS/Battery (Short-term) ──→ Instantaneous uninterrupted guarantee

Backup Strategy:

  • Generator: Hours to days operation (fuel-dependent)
  • UPS: Minutes to tens of minutes operation (battery capacity-dependent)
  • Combined effect: UPS covers generator startup gap to achieve complete uninterrupted power

4. Operating Scenarios

Scenario 1: Normal Operation

Utility power (15.4KV) → Primary transform (6.6KV) → Secondary transform (380V) → UPS → DC load (48V)

Scenario 2: Momentary Power Outage

  1. Main power interruption detected (< 4ms)
  2. UPS battery immediately engaged
  3. Continuous power supply to load with zero interruption

Scenario 3: Extended Power Outage

  1. Main power interruption detected
  2. UPS battery immediately engaged (maintains uninterrupted power)
  3. Generator automatically starts (10-30 seconds required)
  4. Generator reaches rated capacity and replaces main power
  5. Generator power charges UPS + supplies load
  6. Long-term operation with continuous fuel supply

Scenario 4: Generator Failure

  • Limited-time operation within UPS battery capacity
  • Priority operation for critical systems or graceful shutdown

5. Additional Protection and Control Devices

Supplementary devices for system stability and safety:

Circuit Breaker Hierarchy

  • GCB (Generator Circuit Breaker): Primary protection at reception point
  • VCB (Vacuum Circuit Breaker): Vacuum interruption, medium voltage protection
  • ACB (Air Circuit Breaker): Low voltage distribution panel protection
  • MCCB (Molded Case Circuit Breaker): Individual load protection
  • Role: Circuit interruption during overload or short circuit to protect equipment and personnel

Switching Devices

  • STS (Static Transfer Switch): High-speed transfer between main power ↔ generator
  • ATS (Automatic Transfer Switch): Automatic transfer between power sources ( UPS level)
  • ALTS (Automatic Load Transfer Switch): Automatic load transfer ( for 22.9kV class)
  • CCTS: Circuit breaker control and transfer system
  • Role: Automatic/immediate transfer to backup power during power failure

Switching Points (Red circle indicators)

  • Reception point, before/after transformers, backup power injection points
  • Critical points for power path changes and redundancy implementation

6. Key System Features

✅ Uninterruptible Power Supply: Three-stage protection with main power → generator → UPS
✅ Multi-stage Voltage Conversion: Ensures both transmission efficiency and usage safety
✅ Automated Backup Transfer: Automatic switching without human intervention
✅ Hierarchical Protection: Stage-by-stage circuit breakers prevent cascading failures
✅ Scalable Architecture: Modular configuration enables easy capacity expansion

Summary

This DC power system architecture ensures continuous, uninterrupted operation of mission-critical data center infrastructure through a sophisticated combination of redundant power sources, automated failover mechanisms, and multi-layered protection systems. The integration of long-term generator backup and short-term UPS battery systems creates a seamless power continuity solution that can handle any grid interruption scenario. The multi-stage voltage transformation (15.4KV → 6.6KV → 380V → 48V DC) optimizes both transmission efficiency and end-user safety while providing flexibility for diverse IT equipment requirements.

#DataCenter #DCPower #PowerSystems #CriticalInfrastructure #UPS #BackupPower #DataCenterDesign #ElectricalEngineering #PowerDistribution #MissionCritical #DataCenterInfrastructure #FacilityManagement #PowerReliability #UninterruptiblePowerSupply #DataCenterOperations

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‘tightly fused’

Posted on by lechuck park

This illustration visualizes the evolution of data centers, contrasting the traditionally separated components with the modern AI data center where software, compute, network, and crucially, power and cooling systems are ‘tightly fused’ together. It emphasizes how power and advanced cooling are organically intertwined with GPU and memory, directly impacting AI performance and highlighting their inseparable role in meeting the demands of high-performance AI. This tight integration symbolizes a pivotal shift for the modern AI era.

Switching of the power

Posted on by lechuck park

This diagram illustrates two main power switching methods used in electrical systems: ATS (Automatic Transfer Switch) and STS (Static Transfer Switch).

System Configuration

  • Power Sources: Utility grid and Generator
  • Protection: UPS systems
  • Load: Server infrastructure

ATS (Automatic Transfer Switch)

Location: Switchgear Area (Power Distribution Board)

Characteristics:

  • Mechanism: Mechanical breakers/contacts
  • Transfer Time: Several seconds (including generator start-up)
  • Advantages: Relatively simple, lower cost
  • Application: Standard power transfer systems

STS (Static Transfer Switch)

Location: Panelboard Area (Distribution Panel)

Characteristics:

  • Mechanism: Semiconductor devices (SCR, IGBT)
  • Transfer Time: A few milliseconds (near seamless)
  • Advantages: Ensures high-quality power supply
  • Disadvantages: Expensive

Key Differences

  1. Transfer Speed: STS is significantly faster (milliseconds vs seconds)
  2. Technology: ATS uses mechanical switching, STS uses electronic switching
  3. Cost: ATS is more economical
  4. Power Quality: STS provides more stable power delivery
  5. Complexity: STS requires more sophisticated semiconductor control

Applications

  • ATS: Suitable for applications that can tolerate brief power interruptions
  • STS: Critical for sensitive equipment like servers, data centers, and medical facilities requiring uninterrupted power

Summary: This diagram shows a redundant power system where ATS provides cost-effective backup power switching while STS offers near-instantaneous transfer for critical loads. Both systems work together with UPS backup to ensure continuous power supply to servers and sensitive equipment.

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LLM Efficiency with a Cooling

Posted on by lechuck park

This image demonstrates the critical impact of cooling stability on both LLM performance and energy efficiency in GPU servers through benchmark results.

Cascading Effects of Unstable Cooling

Problems with Unstable Air Cooling:

  • GPU Temperature: 54-72°C (high and unstable)
  • Thermal throttling occurs – where GPUs automatically reduce clock speeds to prevent overheating, leading to significant performance degradation
  • Result: Double penalty of reduced performance + increased power consumption

Energy Efficiency Impact:

  • Power Consumption: 8.16kW (high)
  • Performance: 46 TFLOPS (degraded)
  • Energy Efficiency: 5.6 TFLOPS/kW (poor performance-to-power ratio)

Benefits of Stable Liquid Cooling

Temperature Stability Achievement:

  • GPU Temperature: 41-50°C (low and stable)
  • No thermal throttling → sustained optimal performance

Energy Efficiency Improvement:

  • Power Consumption: 6.99kW (14% reduction)
  • Performance: 54 TFLOPS (17% improvement)
  • Energy Efficiency: 7.7 TFLOPS/kW (38% improvement)

Core Mechanisms: How Cooling Affects Energy Efficiency

  1. Thermal Throttling Prevention: Stable cooling allows GPUs to maintain peak performance continuously
  2. Power Efficiency Optimization: Eliminates inefficient power consumption caused by overheating
  3. Performance Consistency: Unstable cooling can cause GPUs to use 50% of power budget while delivering only 25% performance

Advanced cooling systems can achieve energy savings ranging from 17% to 23% compared to traditional methods. This benchmark paradoxically shows that proper cooling investment dramatically improves overall energy efficiency.

Final Summary

Unstable cooling triggers thermal throttling that simultaneously degrades LLM performance while increasing power consumption, creating a dual efficiency loss. Stable liquid cooling achieves 17% performance gains and 14% power savings simultaneously, improving energy efficiency by 38%. In AI infrastructure, adequate cooling investment is essential for optimizing both performance and energy efficiency.

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Emergency Power System

Posted on by lechuck park

This image shows a diagram of an Emergency Power System and the characteristics of each component.

Overall System Structure

At the top, the power grid is connected to servers/data centers, and three backup power options are presented in case of power supply interruption.

Three Backup Power Options

1. Generator

  • Long-term operation: Unlimited operation as long as fuel is available
  • Operation method: Engine rotation → Power generation
  • Type: Diesel engine generator
  • Disadvantages:
    • Start-up delay during instantaneous power outages
    • Start-up delay, noise, exhaust emissions
    • Periodic testing required
    • Requires integration with ATS (Automatic Transfer Switch)

2. Dynamic UPS

  • Features:
    • Uninterrupted/Long-term operation (until diesel engine starts)
    • Flywheel kinetic energy storage
    • Combined generator and diesel engine
  • Advantages: Seamless power supply without STS (Static Transfer Switch)
  • Disadvantages: High initial cost, large footprint, noise

DR (Diesel Rotary) UPS: A special form of Dynamic UPS that provides uninterrupted power through flywheel energy storage technology.

3. Static UPS

  • Operation time: Instantaneous/Short-term (typically 5-15 minutes)
  • Power quality: Clean power supply
  • Configuration: Battery(DC) → Inverter(AC) → Rectifier
  • Features:
    • Millisecond-level instant transfer
    • Battery life 3-5 years, replacement costs, heat generation issues

Key Characteristics Summary

Generators can operate long-term with fuel supply but have start-up delays, while Static UPS provides immediate power but only for short durations. Dynamic UPS (including DR UPS) is a hybrid solution that provides uninterrupted power through flywheel technology while enabling long-term operation when combined with diesel engines. In actual operations, it’s common to use these systems in combination, considering the advantages and disadvantages of each system.

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Power Circuit Breaker

Posted on by lechuck park

This image presents a Power Circuit Breaker classification diagram showing the types and characteristics of electrical circuit breakers used in power systems.

System Overview

Power Flow: The diagram illustrates the electrical power path from power plant → transmission lines → circuit breakers → distribution panels.

Circuit Breaker Classification

The breakers are categorized by voltage levels and arc extinguishing methods:

Voltage Classifications

  • Very High Voltage: 66~800kV
  • High Voltage: 3.3~38kV
  • Using Voltage: 380~690V, 110~600V, 110~440V

Breaker Types and Arc Extinguishing Methods

  1. GIS/GCB (Gas Insulated Switchgear/Gas Circuit Breaker)
    • 66~800kV
    • Uses SF6 gas with high vacuum technology
  2. VCB (Vacuum Circuit Breaker)
    • 3.3~38kV
    • Vacuum arc extinguishing method
  3. ACB (Air Circuit Breaker)
    • 380~690V
    • Air + arc chute method
  4. MCCB (Molded Case Circuit Breaker)
    • 110~600V
    • Air + arc chute method
  5. ELCB (Earth Leakage Circuit Breaker)
    • 110~440V
    • Ground fault protection, no arc extinguishing

Key Safety Message

The diagram emphasizes “The bigger (Arc) the more dangerous” – highlighting that higher voltages require more sophisticated and safer arc extinguishing technologies.

Summary: This technical diagram systematically categorizes power circuit breakers from ultra-high voltage (800kV) to low voltage (110V) applications, demonstrating how arc extinguishing complexity increases with voltage levels. The chart serves as an educational reference showing that higher voltage systems require more advanced safety mechanisms like SF6 gas insulation, while lower voltage applications can use simpler air-based arc interruption methods.

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Data Center ?

Posted on by lechuck park

This infographic compares the evolution from servers to data centers, showing the progression of IT infrastructure complexity and operational requirements.

Left – Server

  • Shows individual hardware components: CPU, motherboard, power supply, cooling fans
  • Labeled “No Human Operation,” indicating basic automated functionality

Center – Modular DC

  • Represented by red cubes showing modular architecture
  • Emphasizes “More Bigger” scale and “modular” design
  • Represents an intermediate stage between single servers and full data centers

Right – Data Center

  • Displays multiple server racks and various infrastructure components (networking, power, cooling systems)
  • Marked as “Human & System Operation,” suggesting more complex management requirements

Additional Perspective on Automation Evolution:

While the image shows data centers requiring human intervention, the actual industry trend points toward increasing automation:

  1. Advanced Automation: Large-scale data centers increasingly use AI-driven management systems, automated cooling controls, and predictive maintenance to minimize human intervention.
  2. Lights-Out Operations Goal: Hyperscale data centers from companies like Google, Amazon, and Microsoft ultimately aim for complete automated operations with minimal human presence.
  3. Paradoxical Development: As scale increases, complexity initially requires more human involvement, but advanced automation eventually enables a return toward unmanned operations.

Summary: This diagram illustrates the current transition from simple automated servers to complex data centers requiring human oversight, but the ultimate industry goal is achieving fully automated “lights-out” data center operations. The evolution shows increasing complexity followed by sophisticated automation that eventually reduces the need for human intervention.

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