How to install current transformer1. The construction shall be carried out according to the drawing, the wiring shall be correct, the number marks at both ends of the conductor shall be clear, and the label range shall meet the requirements of the specification.2. The secondary circuit conductor or cable shall be copper wire. The section of current transformer circuit conductor shall not be less than 2.5mm2, and the section of voltage transformer circuit conductor shall not be less than 1.5mm2
3. Special current terminals shall be selected for the first terminal block at the outlet of the current transformer, and the secondary winding not used by the current transformer shall be short circuited and grounded at the terminal block.4. There shall be no joint for the secondary circuit conductor in the panel and cabinet, and there shall be no joint in the middle of the control cable or conductor. If there must be a joint, the long terminal box shall be used for transition connection.5. The polarity of current transformer shall not be reversed, and the phase sequence and phase shall meet the requirements of design and regulations. For the wiring of transformer for differential protection, the current phasor diagram of two arms must be measured before putting into operation to check the correctness of wiring.
6. The arrangement of secondary circuit conductors shall be neat and beautiful, the connecting screws between conductors and electrical components and terminal strip must be free of virtual connection and looseness, and the distance between conductor binding and clamping points shall meet the requirements of the regulations.7. The secondary circuit shall be well insulated from the ground, and there shall be no mixed line between the voltage circuit and the current circuit.8. The current and voltage circuits shall be grounded at one point at the outlet of the secondary side of the transformer.
Current transformer installation specification1. The current transformer must be installed firmly, and the exposed metal part of the transformer shell shall be reliably grounded.2. The same group of current transformers shall be installed in the same direction to ensure that the positive directions of the primary and secondary circuit currents of this group of current transformers are consistent, and it is easy to observe the nameplate as much as possible.
3. Open circuit is not allowed at the secondary side of current transformer. When only one secondary circuit is used for secondary double turn transformer, the other secondary circuit shall be reliably short circuited.
4. The secondary side of low-voltage current transformer can not be grounded. Because the insulation grade of conductor, watt hour meter and transformer used by low-voltage metering device is the same, the maximum voltage that can be borne is basically the same; In addition, after the secondary winding is grounded, the insulation level of the primary circuit of the whole device to the ground is reduced, which is easy to damage the watt hour meter or transformer with insulation weakness under the action of high voltage (such as induced lightning stroke). In order to reduce lightning damage, it is also better to have the secondary side ungrounded.
Precautions for use of current transformer1. When measuring CT with magnetic shunt compensation, there may be a large difference between the error value measured by the instrument and the error value measured by the traditional method, which is determined by the test method of the tester. Because the compensation amount of magnetic shunt compensation cannot be measured on the basis of this test method; However, under 100% and 120% current percentage, the verification conditions of the instrument are met.2. There is no display after startup. Please check whether the power supply is connected properly and whether the fuse is blown.
3. In the storage record, the storage time is garbled. Currently, empty data is stored, and the stored data in the storage record is checked again under continuous power down.4. This interface is a general platform based on Huatian power development, and the display part is separated from the measurement part. When measuring an item, although the "Cancel" key exits the page of the current measurement item, the instrument is still measuring the item. Do not touch the tested object and test clip!5. Please press the "reset" button or shut down the instrument in case of any crash, splash screen or white screen of the instrument, or interrupt the measurement of the instrument.
6. Since the display part of the instrument is separated from the measurement part, when any interface displays all asterisks, the instrument cannot communicate. If repeated "reset" and shutdown cannot be repaired, the instrument has been damaged.
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