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Gabo Co., Ltd. will become a company that impresses customers with the best quality and best service.

      TRANSFORMER PROTECTION PANEL

      Product Overview

      Transformer protection panelPower transmission is done through remote route between power station and receiving-end. And the efficiency of transmission is directly related to an economic feasibility.

      Thus, generation voltage is stepped up and transmitted to receiving-end through remote grid. At a receiving-end, through stepping down, a power gets supplied while caring safety of distribution network and power customer.

      This process of step up and step down is done by power transformer that which is one of the power facilities. Power transformer is important because it influences efficiency, safety, and stability of power transmission.

      Power transformer is not only one of expensive power facilities which need long time for maintenance and contains multiple potential problems. Problem of power transformer can lead outage of power customer. Thus power transformer protection is directly related to power quality issue, making reliability important.

      Protection relay needed for protection of transformer has current differential function as main protection. And for back up protection, over current protection is used in each primary side and in secondary side. Especially in secondary side, for NGR protection, ground over voltage protection relay is applied.

      GABO’s transformer protection panel has a main protection relay 7UT6x made from SIEMENS, in order to guarantee reliability. By having accumulated knowledge in manufacturer technology of protection panel, and experienced professionals, we strive to accomplish noise immunity, stable earthing, durability, insulation, assembly, all of which being incorporated in order to generate products of credibility.

      TRANSFORMER PROTECTION SYSTEM CONFIGURATION

      Transformer protection relay measures current of primary and secondary current, and by using the measurement, it calculates restraint current and differential current. Thus transformer protection relay decides any existence of transformer internal/external fault by using ratio current differential relaying function.
      In a transformer, depends on number of winding, it is divided into 2 winding and 3 winding transformer. And current differential relaying function gets calculated by sum of all winding’s current.

      • 7UT85

        Two winding transformers
        (2 sides, 4 measuring points)

      • 7UT86

        Three winding transformers
        (3 sides, 5 measuring points)

      • 7UT87

        Multiple winding transformers
        (5 sides, 7 measuring points)

      TRANSFORMER MAGNETIZING INRUSH CURRENT DETECTION

      A magnetizing inrush current occurs when circuit breaker gets closed and transformer becomes initially energized.
      This magnetizing inrush current occurs in primary side and does not pass on to secondary side, which causes differential current between two sides. The differential current function needs a function that prevents mal-operation caused by magnetizing inrush current.

      TRANSFORMER PROTECTION RELAY(7UT8x)

      • - Digital Protection Relay with 32 Bit high-speed microprocessor
        - Up to 5 winding transformer current differential protection
        - Stable Dual-Slope characteristics
        - Phase shift automatic compensation by using 12 Matrix
        - Automatic compensation on primary and secondary currency mismatch by using transformer’s a rated current
        - Magnetizing inrush current detection through second harmonic blocking element
        - Current auto-compensation to CT saturation and CT ratio error, tap changer
        - Convenient function such as Remote setting/ Fault analysis by software

      RATIO DIFFERENTIAL CHARACTERISTICS CURVE

      • A ratio current differential characteristic for transformer protection is divided into trip area and non-trip area by ratio between restraint current (scalar sum) and that of differential current (vector sum).
        In case of transformer protection, it uses phase compensation decided from primary and secondary winding connection. Phase compensation uses vector group such as 30 [deg] x 12 in order to compensate phase difference and to prevent maloperation by zero sequence current.

      MAIN FUNCTION

      - Current Differential Protection (Independent Protection for Each Phase)
      - 2nd Harmonic Suppression Element
      - Automatic Compensation for Current Phase and Magnitude based on Transformer Winding and Turns Ratio
      - Automatic Compensation for Saturation and Error
      - Instantaneous/Time Overcurrent Protection (Backup Protection)
      - Instantaneous/Time Earth Fault Protection (Backup Protection)
      - Earth Fault and Voltage Protection (Backup Protection)

      - User Logic Implementation Capability
      - Malfunction Prevention via Various Fault Detection Functions
      - Self-Diagnostic Function
      - Single/Three Phase Trip Function
      - Metering Function (Current, Voltage, Active/Reactive Power, etc.)
      - Event Recording Function (Trip, Alarm, Failure, etc.)
      - Calibration and Fault Analysis Function Using Local PC
        (Analysis Programs such as DIGSI, Standard File Conversion Function (Comtrade))

      TECHNICAL SPECIFICATION/STANDARD

      Index Item Specification
      Rating Power Supply Voltage Input DC : 48~300[V], AC : 80~265[V] (Frequency 50/60[hz])
      Power Consumption Modular Type : Basemodule standard DC 13[W], AC 55[VA]/ Per expansion module : DC 3W, AC 6VA
      Analog Current(CT) 1[A] or 5[A], Burden : Approx. 0.1[VA]
      Power(PT) 0~200[V], Power Consumption < 0.1[VA]
      Digital input Number of input : Selectable by applying multiple expansion modules
      Voltage range : 24 ~ 300[VDC]
      Digital Output Number of output : Selectable by applying multiple expansion modules
      Allowable current : 5[A](Continuous), 30A for 1s, 250A for 30ms
      Communication Communication Port RS-232, RS-485, Ethernet, FO(Fiber Optic)
      Protocol Profibus, DNP3.0, IEC61850, TCP/IP
      Time Synchronization DCF77/IRIG-B/SNTP/IEEE 1588