TT Systems

Characteristics

TTsystems have one point connected directly to ground and all exposed conductive parts of the installation must be connected to an earth electrode. This earth electrode is independent of the power system earthed point.

Reference to IEC 60364-4-41 413.1.4

All exposed conductive parts that are protected collectively by the same protective device must be connected to a common earth electrode together with the protective conductors. In installations where several protective devices are utilized in series, the requirement applies separately to all exposed conductive parts protected by each device.

The neutral point or, if a neutral point does not exist, a phase conductor of each generator station or transformer station must be earthed.

Protective devices in TT systems

The following protective devices are recognized in TT systems:

•Overcurrent protective devices

•Residual current protective devices

Overcurrent protective devices are only applicable for protection against indirect contact in TT systems where a low RA value exists (see specification below).

The condition RA ⋅ Ia ≤ 50V must be fulfilled.

In the condition:

RA

is the sum of resistance of the earth electrode and the protective conductor for the exposed

 

conductive parts

Ia

is the current causing the automatic operation of the protective device.

 

When the protective device is a residual current protective device, Ia is the rated residual operating

 

current IΔ n

For discrimination purposes, S-type residual current protective devices may be used in series with general type residual current protective devices. To provide discrimination with S-type residual current protective devices, an operating time not exceeding 1 second is permitted in distribution circuits.

Symmetra MW 800 kW 3 × 400/230 V Installation - 990-1510D

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American Power Conversion SYMF800KH manual TT Systems, Protective devices in TT systems
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SYMF800KH specifications

American Power Conversion (APC), a subsidiary of Schneider Electric, is renowned for its expertise in providing reliable power solutions. Among its extensive product lineup, the SYMF800KH stands out as a cutting-edge uninterruptible power supply (UPS) designed to meet the demands of enterprise data centers and critical applications. This model is particularly valued for its impressive performance, adaptability, and advanced technologies.

One of the main features of the SYMF800KH is its capability to deliver an output power of 800 kVA, making it suitable for high-density loads. This UPS operates in a parallel configuration, allowing for scalability by connecting multiple units to provide increased capacity and redundancy. This adaptability ensures that organizations can grow their infrastructure without worrying about power limitations.

Another significant characteristic of the SYMF800KH is its high-efficiency operation that helps reduce energy costs and carbon footprint. With a near-unity power factor and up to 97% efficiency in double conversion mode, the SYMF800KH minimizes energy losses, benefiting both the environment and the organization's operational expenses.

The SYMF800KH is equipped with advanced technologies to ensure maximum reliability and performance. Its innovative SmartBoost and SmartTrim features enhance the UPS's ability to manage input voltage variations and optimize output voltage levels, safeguarding sensitive equipment from potential damage. The unit also boasts an intelligent battery management system, extending battery life and ensuring consistent performance during power outages.

Moreover, the SYMF800KH provides robust monitoring and management options. It is compatible with APC's software solutions, allowing users to monitor real-time data, receive alerts, and conduct remote management from a centralized interface. This feature is critical for maintaining operational reliability and ensuring timely response to any potential power issues.

In addition to its performance capabilities, the SYMF800KH is designed with ease of maintenance in mind. Its modular architecture allows for quick and straightforward replacement of components, minimizing downtime during service activities.

In conclusion, the American Power Conversion SYMF800KH is a high-performance UPS that brings together reliability, efficiency, and advanced technology, making it an ideal choice for organizations seeking to protect their critical infrastructure. By delivering scalable solutions with enhanced management features, the SYMF800KH stands as a top contender in the uninterruptible power supply market. As businesses continue to rely on technology for their daily operations, the importance of such robust power solutions cannot be overstated.
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