Product Introduction

       ND702-3H Microcomputer-Based Relay Protection Tester is a new type of compact microcomputer relay protection tester developed with reference to the "Technical Conditions for Microcomputer-Based Relay Protection Test Devices (Discussion Draft)" issued by the Ministry of Electric Power. It incorporates extensive user feedback, summarizes the strengths and weaknesses of similar domestic products, and fully utilizes modern advanced microelectronic technologies and components.

       The microcomputer relay protection tester adopts an advanced structure that can operate independently as a standalone unit or be connected to a laptop computer. The main unit is equipped with a new generation of high-speed digital signal processor microcomputers, true 16-bit DAC modules, and new modular high-fidelity high-power amplifiers. It features a large-screen LCD display and a flexible, user-friendly rotary mouse controller. The standalone operation already offers robust functionality for most tests, while connection to a computer provides even more powerful operational capabilities. It is compact, highly accurate, and combines the superior performance and advanced features of large testers with the small size, flexibility, ease of operation, and high reliability of compact testers, offering excellent cost-effectiveness. It is an indispensable tool for relay protection professionals.

Product Features

☆、This microcomputer relay protection tester uses a high-speed, high-performance digital control processor as the control microcomputer, employing double-precision algorithms in the software to generate highly accurate waveforms for each phase;

☆、Utilizes high-speed, high-bit D/A converters to ensure the accuracy and linearity of current and voltage across the entire range;

☆、The power amplifier circuit uses imported high-power, high-fidelity modular power devices as the output stage, combined with a carefully and rationally designed heat dissipation structure, providing sufficient power redundancy and thermal capacity;

☆、The switch input circuit is compatible with dry contacts and 0～250V potential contacts;

☆、The instrument features a 320×240 dot matrix high-resolution blue backlit LCD screen as the display;

☆、The device is equipped with a dedicated adjustable DC power output on the chassis baseplate, available in 110V and 220V ranges, which can serve as an auxiliary power source for field testing.

Technical Parameters

AC Current Source

Three-phase current source with a common neutral point, current rise/fall time <100μs

Output power: 300VA/phase

Output accuracy:

0.1A～2A accuracy ±20mA

2A～40A accuracy ±0.5%

Single-phase continuous output time:

0.1A～5A output time Unlimited

5A～10A output time ≥60 seconds

10A～20A output time ≥30 seconds

20A～30A output time ≥3 seconds

30A～40A output time ≥2 seconds

Resolution: 10mA

AC Voltage Source

Four-phase voltage source with a common neutral point, current rise/fall time <100μs

Output power: ≥75VA/phase

Output accuracy:

1V～5V accuracy ±20mV

5V～125V accuracy ±0.5%

Resolution: 10mV

DC Current Source

Single-phase output range: -10A～+10A or 0～20A

Output power: 200VA/phase

Output accuracy:

±0.1A～±2A accuracy ±20mA

±2A～±10A accuracy ±0.5%

Resolution: 10mA

DC Voltage Source

DC voltage output range: -150V～+150V or 0～300V

Output power: ≥100VA

Output accuracy:

±1V～±5V accuracy ±20mV

±5V～±150V accuracy ±0.5%

Resolution: 10mV

AC Voltage and Current Source Phase Angle

Phase angle range: 0°～ 360°

Accuracy: ±0.5°

Resolution: 0.1°

AC Voltage and Current Source Frequency

Frequency range: 10～1000Hz

Capable of superimposing 2nd to 20th harmonics of arbitrary amplitude and DC component

Output accuracy:

10Hz～65Hz ±0.01Hz

65Hz～1000Hz ±0.02Hz

Resolution: 0.001 Hz

Timing Accuracy

1ms～1S ±10ms

1S～9999S ±0.5%

Input Contacts

8 independent switch contact inputs, automatically identifying the polarity of active contacts

Compatible with dry contacts and 15V～250V active contacts

Output Contacts

4 pairs of programmable switch dry contact outputs

Contact capacity: 250VDC, 0.5A or 250VAC, 0.5A

Synchronization

Voltage and current synchronization ≤50μS

Power Supply

AC input voltage:

Rated value: 220V ± 10%

Reference value: 220V ± 2%

AC power supply frequency:

Rated value: 50Hz ± 10%

Reference value: 50Hz ± 2%

Operating Environment

Ambient temperature: －10℃～+40℃

Relative humidity: ≤90%

Atmospheric pressure: 80～110kPa

Chassis Dimensions and Weight

Chassis dimensions (L×W×H): 420mm×190mm×470mm

Weight: 20 kilograms