杏悦2官网

Overview

In power supply and distribution circuits,the current varies widely,ranging from a few amperes to tens of thousands of amperes.To facilitate measurement by instruments and meters,it is necessary to convert this into a relatively uniform current.Additionally,the voltage on power supply and distribution lines is generally high,making direct measurement extremely dangerous for both the instruments and personnel.Therefore,current transformers are commonly used in power systems to measure primary current,serving the dual purposes of current transformation and electrical isolation.

The ENR-LJ(K)series zero-sequence current transformers produced by Baoding Yinuoer Electric Equipment Co.,Ltd.have been tested by the Electrical Equipment Quality Testing Center of the Ministry of Electric Power Industry.Their quality exceeds the national standard GB1208-1997"Current Transformers,"featuring high precision,excellent linearity,reliable operation,easy installation,and an attractive appearance.

Zero-sequence current transformers(cable type)with apertures ranging fromФ40 toФ360 are available,including high-precision zero-sequence current transformers with various capacities,ratios,and accuracy limit coefficients,as well as highly sensitive zero-sequence current transformers compatible with small current grounding line selection devices and relays.The products are divided into two categories:integral type and combined type.The transformers feature engineering plastic casings and fully sealed resin potting,offering an appealing appearance,easy installation,space-saving design,and a wide range of specifications to meet the needs of various protection devices and power system operating modes(neutral grounding,neutral non-grounded,high-resistance grounding,low-resistance grounding,and arc suppression coil grounding).

II.Model Meaning

III.Usage Conditions

1.Ambient temperature:Maximum temperature+60℃,daily average not exceeding+40℃,minimum temperature-5℃;

2.Altitude:Not exceeding 1000m(special order required for highland use);

3.Relative humidity:<85%;

4.AC voltage above 0.4A(cable);

5.Grid frequency is 50Hz.

IV.Working Principle

The zero-sequence current transformer operates on the same principle as a current transformer,consisting of a secondary coil,iron core,insulation support,and output terminals.It serves as a zero-sequence current filter,with its secondary side reflecting the zero-sequence current of the primary system.This type of current transformer encloses the three-phase conductors(busbars or cables)within a single iron core,with the secondary winding wound around the same enclosed core.

Under normal conditions,since the primary three-phase currents are balanced,their vector sum is zero,resulting in no magnetic flux being generated in the iron core and no current in the secondary winding.In the event of a single-phase ground fault in the system,the sum of the three-phase currents becomes non-zero(equal to three times the zero-sequence current),causing zero-sequence magnetic flux to appear in the iron core.This flux induces an electromotive force in the secondary winding,driving a current through the relay and triggering its operation.

V.Installation

1.Integral-type transformers must be installed before laying the cable,with the cable passing through the transformer during installation.

2.Polarity terminal:The primary side passes through the"P1(L1)"side of the transformer,and the secondary side is"S1(K1)".

3.The split-core current transformer is not limited by cable installation,with specific methods as follows:

3.1 Remove the connection tabs at"S/1(K/1)"and"S/2(K/2)"of the transformer;

3.2 Loosen and remove the two hex socket bolts at the top of the transformer,which will separate it into two parts;

3.3 Place the transformer around the cable,clean both contact surfaces,apply a thin layer of anti-rust oil,align the two parts of the transformer,and then tighten the hex socket bolts,ensuring proper alignment to avoid affecting performance;

3.4 Secure the connection tabs to"S/1(K/1)"and"S/2(K/2)";

3.5 split-core current transformers have upper and lower parts that are not interchangeable with other transformers.

VI.Ordering Instructions

Due to the rapid development of power systems,diverse operation modes,and the continuous emergence of various types of protection and devices—along with the import of a large number of protection devices—there is a wide variety of zero-sequence current transformers required.Our company can design and produce zero-sequence current transformers of various specifications and aperture sizes,as well as matching transducers for protection devices,according to customer needs.For model selection,please refer to Appendix Table 1 and Table 2.When placing an order,please provide the following parameters:

1.Product model,inner hole diameter(mm);

2.Primary zero-sequence current,secondary current(or current ratio);

3.Secondary load capacity or load impedance;

4.Accuracy limit factor,accuracy class(if applicable);

5、、、Opening type:Open type or integral type;

6、、、Installation location:Indoor or outdoor.

Note:Φ8.5 four holes are through holes,B and C are the dimensions between the four holes,suitable for horizontal installation.

Data and dimensions of ABS shell cast-type zero-sequence current transformer(see Table 1,Table 2)