110kV/220kV Substation Series Testers

  • JYC Dielectric Loss/ Tan delta Tester (OTD) Tester
JYC Dielectric Loss/ Tan delta Tester (OTD) Tester

JYC Dielectric Loss/ Tan delta Tester (OTD) Tester

  • Dissipation Factor Testing
  • CVT test function
  • Strong anti- interference
  • Fast test speed
  • Product description: JYC Transformer dielectric loss/Tan Delta(OTD) tester has anti interference function by frequency conversion during dielectric tan delta testing, and it is not necessary to change wire as CVT testing,

What Is Tan δ, Or Tan Delta?
Oil Tan Delta(OTD), also called Loss Angle or Dielectric Dissipation Factor (DDF) or Power Factor (PF) testing, is an electrical dielectric test on the insulating oil used to determine its quality. The test is performed at two temperatures. Information from each test and the results considered together may form the basis for making a judgment on whether it’s suitable for a transformer to continue in service and for determining when the replacement or regeneration of the transformer oil is needed.

Changes in capacitance can, for example, indicate mechanical displacements of winding or partial breakdown in bushings. Aging and degradation of the insulation, coupled with the ingress of water, increase the amount of energy that is converted to heat in the insulation. The rate of these losses is measured as dissipation factor.

Principle of Tan Delta Test
A pure insulator when is connected across line and earth, it behaves as a capacitor. In an ideal insulator, as the insulating material which acts as dielectric too, is 100 % pure, the electric current passing through the insulator, only have capacitive component. There is no resistive component of the current, flowing from line to earth through insulator as in ideal insulating material, there is zero percent impurity.
In pure capacitor, the capacitive electric current leads the applied voltage by 90°.
In practice, the insulator cannot be made 100% pure. Also, due to the aging of insulators, the impurities like dirt and moisture enter into it. These impurities provide the conductive path to the current. Consequently, an electric leakage current flowing from line to earth through the insulator has a resistive component.
Hence, it is needless to say that, for a good insulator, this resistive component of electric leakage current is quite low. In another way, the healthiness of an electrical insulator can be determined by the ratio of the resistive component to the capacitive component. For a good insulator, this ratio would be quite low. This ratio is commonly known as tan δ or tan delta. Sometimes it is also referred to as dissipation factor.

1. Dielectric breakdown (BDV) (ASTM D877 & ASTM D1816, IEC 60156)

2. Tan Delta (Dielectric Dissipation Factor (DDF)/ Power factor) (ASTM D924, IEC 60247, IEC 61620, BS 5737, JIS C2101, VDE 0380-2, IS 6262)

3. Resistivity (ASTM D1169, IEC 60247, BS 5737, JIS C2101, VDE 0380-2, IS 6103)

JYC automatic frequency conversion anti-interference dielectric loss tester is used for field anti-interference dielectric loss measurement or laboratory precision dielectric loss measurement,the instrument is an integrated structure, built-in dielectric loss bridge, variable frequency power supply, test transformer and standard capacitor, etc., adopts frequency conversion anti-interference and "Fourier" transform digital filtering technology, fully automatic intelligent measurement, the measurement data is very stable under strong interference, and the measurement results are from large to large, LCD screen display, built-in printer can print out.

●Adopt frequency conversion anti-interference technology, automatically identify 50Hz/60Hz system voltage, and can still measure accurately under 200% interference
●With CVT ratio function, it can measure CVT ratio, polarity and phase
●With positive/reverse wiring, internal/external standard capacitance, internal/external high voltage multiple working modes, integrated structure, can do various conventional dielectric loss tests, without any external auxiliary equipment
●With reverse wiring low-voltage shielding function, in the case of CVT bus grounding, it can measure C11 without disconnecting the wire
●With the measurement function of CVT self-excitation method, C1/C2 can be measured at the same time with one connection, and the influence of lead wires and standard capacitor voltage division can be automatically compensated
●It has the function of prompting for bad circuit contact and discharge, to facilitate the judgment of whether the wiring is reliable
●Built-in series and parallel dielectric loss measurement models, used to simulate "Schering bridge" or current comparator bridge, convenient for instrument testing
●Dynamic display of test voltage and current, which can also be used as a high-voltage meter
●Prompt function for poor grounding and poor wiring contact, to facilitate judging whether the wiring is reliable
Strong power adaptability, can use 50/60Hz power supply, strong anti-interference and can also support generator power supply
●With calendar clock, can store 100 sets of measurement data, with RS232 computer interface, through this interface, can realize measurement, data processing and test result output; equipped with computer background software, can be integrated into comprehensive test vehicle inspection

Optional features
●Optional four-channel positive wiring test mode, convenient for transformer bushing dielectric loss test
●Optional insulation resistance test function:
a. The wiring of the insulation resistance is exactly the same as that of the dielectric loss testing, and the shielding method suitable for the dielectric loss testing is the same as that of the insulation resistance; when measuring the insulation resistance, there is no need to increase any wiring workload:

b. The operation is simple, just select "resistance" from the menu /Absorption/Polarization" to start the testing;
c. High reliability, and it will not cause damage to the instrument when used in harsh test environments:
d. When measuring insulation resistance, the instrument has excellent anti-interference ability, and it can also measure accurately under 5mA power frequency interference, and has a fast discharge function
●Optional CT ratio function, which can measure CT ratio, polarity and phase
●Optional wireless bluetooth communication to realize wireless control and data transmission between computer and instrument ●Optional frequency-by-frequency test function, you can choose any frequency test from 45 to 65Hz
●External standard capacitor interface is optional, supporting external test power supply of 30Hz~300Hz. External large-capacity power frequency power supply can realize large-capacity high-voltage dielectric loss test



JYC Dielectric Loss (Tan Delta)Tester


Cx: ±(Reading×1%+2pF)

tgδ: ±(Reading×1%+0.00040)

Anti-interference index

With frequency conversion anti-interference, the above accuracy can be achieved under 200% interference.

Capacitance range

Internal application of high voltage: 3pF60,000 pF/10kV, 60pF1µF/0.5kV

External application of high voltage: 3pF1.5µF/10kV, 60pF30µF/0.5kV

Resolution: Max. 0.001pF, 4 valid digits

Range of tgδ

No limit, resolution:0.001%. Identify capacitive, inductive and resistive tested products automatically.

Test current range


Internal application high voltage

Setting voltage range: 0.510kV

Max. output current: 200mA

Up-down voltage mode: Continuous smoothing

Voltage precision: ±(1.5%×reading+10V)

Voltage resolution: 1V

Testing frequency: 45,50,55,60,65Hz, single frequency

45/55Hz, 55/65Hz, 47.5/52.5Hz, automatic dual frequency

Frequency precision: ±0.01Hz

External application high voltage

Maximum test current at positive connection: 5A, Power frequency or conversion frequency: 4070Hz

Maximum test current at negative connection: 10kV/5A, Power frequency or conversion frequency: 4070Hz

CVT self excitation low voltage output

Output voltage: 350V, output current: 330A

Test time

About 15s, relating to the testing mode

Input power

180V270V AC, 50Hz/60Hz±1%, Grid power or generator

Environmental temperature


Relative humidity

≤80% RH, no dew

Volume / Weight

L430mm*W320mm*H330mm / 29 kg

All KRI tests will adopt international express to reach any corner of the world as fast as 72 hours