XT/PDD-1A Digital Partial  Discharge Detector

I．Application

The series product is a newgeneration of comprehensive testing, analysis, monitoring product for transformerpartial discharge with performance of super anti-interference and mainly appliedto partial discharge detection and on-line monitoring for large powertransformers and other HV electric equipments with a variety of voltage classand capacity.

II.  Product Features

XT/PDD-1A seriesdigital partial discharge detector combines technologies of computer, analogelectronic, high-speed signal acquisition, digital signal processing andgraphics display, ultrasonic testing and various anti-interference and networkcommunication.

1. Partial discharge detection

Introduce signals simultaneously from 5 test points (4 ultrasonic channelsand 1 high-frequency current channel) from transformer, and analyze partialdischarge for transformers or HV electric equipments by electrical method andradio-acoustic method;

Measurement, statistics and analysis of partial discharge repetitiondischarge number;

Analysis for single discharge pulse waveform and determine dischargenature;

Gain range: adjust each channel individually, smooth adjust waveformdisplay at any time and not affect measurement results;

Random interference which is not synchronized with power supply can beremoved effectively by anti-disturbance function of relative filteringtechnology;

Band-pass filter adopts technology of analog and digital mixed-filtering, broadbandcan be combined random, which can restrain various kinds of interferenceefficiently.

Function of partial discharge intelligent recognition can automaticallyidentify interference signals and partial discharge signals at specificcondition, and remove interference.

2. On-line monitoring for partial discharge

The on-line monitoring for partial discharge makes the partial dischargemeasuring technology as the core, utilizes integrated testing method ofelectrical pulse and ultrasonic to record and analyze monitoring data in aperiod, and then get figure of discharge change trend. The system shall sendalarm signal when the monitoring data is more than early warning value. Hiddendangers of partial discharge for transformer and other HV electric equipmentscan be found in time by on-line monitoring for partial discharge, so the earlyforecasting fault can be reached in order to avoid malignant accidents.

Adopting broadband current transformer collects discharge signals of HVelectric equipment through neutral ground circuit or core ground circuit andoil tank ground circuit. Adopting many kinds of anti-interference methods torestrain all kinds of outer noise interference and improve signal to noiseratio, thus, the detection accuracy is increased efficiently.

Multi-channel data collection is adopted by system, which can collect anddeal with discharge signals and ultrasonic signals. The system complex utilizestechnology combination of data and simulating compound filtering, dynamicbandwidth filtering, discharge signal intelligent recognition and otheranti-interference technologies.

Inter-city datatransportation can be realized by internet, so the operating condition ofequipment can be known at any place and time, which can lead the remote on-linemonitor of HV electric equipment (such as transformer) realized.

III. Technical performanceindicator

1.     Main Processor

CPU: SAMSUNG S3C2410 ARM920T;

MEMORY: 64M SDRAM, 64M NAND Flash;

DISPLAY SCREEN: industrial grade high-brightness 3.5-inchtrue color TFT LCD touch screen, display resolution: 320*240;

External interface: LCD touch screen interface, 5-waysignal input interface, RS-232 interface, RS-485 interface.

2.     Working environment:

Environmenttemperature:  -10～45℃    

Relativehumidity：≤ 95%

3.     Measurement channels: 5 channels (4ultrasonic channels, 1 high-frequency current channel)

4.     Sensitivity detection: 10pC

5.     Sampling accuracy:  12Bit

6.     Sampling rate: 20MHz

7.     Measurement range: 10pC～1000nC

8.     Full-scale non-linearerror: 8%

9.     Scale non-linearerror: 5%

10. Scale switch: ×1,×10,×100

11. Measurement frequency band: 3dBboardband 10kHz～1MHz

12. Power supply: AC 220V; frequency 50Hz；power 30W

13.  Dimension:length*width*height(300×200×105）mm