The Sonel MZC-330S is a high-current short-circuit loop impedance meter designed for professionals in the power, electrical, installation, and measurement industries. It combines extensive measuring capabilities with high durability and resistance to harsh working conditions. The device is equipped with a special high-performance ventilation system that significantly reduces the time required to cool the short-circuit resistor, enabling smooth and effective operation without downtime even during repeated high-current measurements.

The MZC-330S is ideal for networks with rated voltages from 110/190 V up to 400/690 V and frequencies of 45-65 Hz. It meets the requirements of EN 61557 and is suitable for use in transformer stations, substations, and industrial installations where prospective fault currents may reach up to 95.8 kA.

Key Features & Advantages

High-Current Measurements (4P Method): The MZC-330S measures very low short-circuit loop impedances with a resolution of 0.1 mΩ using a current of 130 A at 230 V and up to 300 A at 690 V. The 4P (four-pole) method ensures test leads do not require calibration, providing accurate and reliable results even in demanding environments.

Standard Current Measurements (2P Method): For less demanding applications, the meter can perform measurements with a current of 24 A at 230 V (max 37 A at 690 V) with a resolution of 0.01 Ω. This flexibility allows the MZC-330S to be used in a wide range of testing scenarios.

Comprehensive Measurement Capabilities: The meter can measure short-circuit loop parameters, including resistance (RS) and reactance (XS) components. It supports measurements in phase-phase, phase-PE, and phase-N short-circuit systems. The device also differentiates between phase voltage and inter-phase voltage when calculating short-circuit current, enhancing accuracy and safety.

Advanced Connectivity and Remote Control: The MZC-330S features Wi-Fi remote control, allowing users to trigger measurements, save results to memory, and download data from the instrument remotely via a web browser interface. It also offers USB and Bluetooth connectivity for easy data transfer to a PC. The meter can store up to 990 measurement results.

Rugged and Safe Design: With an IP67 rating, the MZC-330S is protected against dust and temporary immersion in water, making it suitable for use in harsh industrial environments. It also meets CAT IV 600V safety standards and includes touch voltage and touch shock voltage measurement with a 1 kΩ resistor, ensuring operator safety during testing.

User-Friendly Interface: The meter features a clear LCD display and an intuitive rotary switch for function selection. It can measure alternating voltage from 0 to 750 V and frequency from 45.0 to 65.0 Hz. The device remembers the last measurement result, even after power-off, unless the function selector position is changed.

Applications

• Substations and Transformer Stations: Measuring fault loop impedance in circuits with high current protection (fuse-links rated at several hundred amperes, motor circuit breakers).
• Industrial Installations: Testing low-voltage networks up to 750 V where prospective fault current may reach 95.8 kA.
• Power Generation: Ensuring electrical safety in power plants and renewable energy facilities.
• Railway Applications: Verifying protection against electric shock in railway power systems.
• Diagnostic and Overvoltage Protection: Assessing short-circuit loop impedance for overvoltage protection devices.