5.2　General Items

5.2.1　The installation of oil-immersed instrument transformer shall be in accordance with the following requirements:

1　Instrument transformers shall be installed horizontally，and arranged in order if they need to be in parallel.The polarity direction of the same group of instrument transformers shall be the same.The position of instrument transformer tap regulating the transformation ratio shall be in accordance with design requirements，and the secondary connection terminal shall be securely connected，well insulated，and clearly marked.

2　The diaphragm of diaphragm-type oil conservator shall be intact.The bolt on the top cover shall be securely tightened，and the level indicator shall be located at the inspection side.The spacer shall be taken down from the breather plug before the power is turned on.

3　The roller of roller-type instrument transformer shall be securely wedged.

4　The grading ring of voltage transformer shall be fitted securely，horizontally and in proper direction.

5　Generally，there is no need to inspect the body of oil-immersed instrument transformer，but it must be checked together with personnel of manufacturer in the event of failure.

5.2.2　The installation of dry-type instrument transformer shall be in accordance with the following requirements:

1　Bus-type instrument transformer:its equipotential spring pivot shall be securely fastened，and the busbar shall be located at the center.The terminals shall be well connected with the busbar without taking additional force.

2　Bushing type instrument transformer:when mounted on the steel frame and its rated current is more than 1500A，it shall have a mechanism for breaking the magnetic circuit.

3　Current transformer:its primary and secondary coils shall not have any broken wire and open circuit.The area of cross section of connection copper wire in the secondary circuit shall not be less than 2.5mm2.

4　Capacitor voltage transformers must be assembled in conformity with according to the product serial number，and they shall not be exchanged with each other.There shall be no short circuit occurring to in the secondary coil，and the oxide on the contact surface of at joints of each component shall be removed and applied with a coat of electrical joint compound（cream）.

5.2.3　The installation of zero-sequence current transformer shall be in accordance with the following requirements:

1　The bus-type zero-sequence current transformer shall be at least 0.5m from the steel frame or wire net；the transformer iron core shall be at least 40-50mm from the fixing steel frame.

2　The cable-type zero-sequence current transformer shall not be less than 0.7m from the cable terminal，and not be less than 1.5-2.0m from other buses and large-current conductors.The cables shall be arranged symmetrically in relation to the center of iron core window.

3　Any magnetic materials shall not be in contact with the iron core or form a magnetic branch circuit together with the instrument transformer.

5.2.4　The installation of reactor shall be in accordance with the following requirements:

1　The reactor shall be installed according to its serial number.Where the three phases are arranged vertically，the winding direction of the coil of the middle phase shall be opposite to that of the other two phases.Where two phases are overlaid with each other and are in parallel with the third phase，the winding direction of the two phases overlaid shall be opposite to each other，but the winding direction of the upper one of the two phases shall be the same as that of the third phase.Where the three phases are arranged horizontally，the winding direction of the three phases shall be the same.Where the three phases are vertically installed，the center line of each phase shall be consistent.

2　Where the reactors are installed one atop another，an insulating board spacer or rubber spacer with a thickness not greater than 4mm shall be placed on the top cap of insulator.The rubber spacer shall be used if the reactors are installed outdoors.

3　Where the rated current is 1500A or above，the bolt made of non-magnetic metal materials shall be used for connecting the bus with the connection terminal of equipment.

4　All of the parts made of magnetic materials in the reactor compartments shall be securely fixed.

5.2.5　The assembly of lightning arrester shall be in accordance with the following requirements:

1　Position of its section shall correspond to the serial number specified by the manufacturer.

2　The oxide film on the metal contact surface at each joint of lightning arrester shall be removed；electrical joint compound shall be applied on the surface.The lead wires of lightning arrester shall be connected in such a way that the terminals should not take an external stress which is greater than the allowable stress.

3　The centers of the three phases of lightning arrester installed in parallel shall be on the same straight line，and the verticality of installation shall meet the manufacturer's requirements.The verticality may be corrected by adding a metal spacer between flanges，to guarantee a desired electrical conduction.The gap in between shall be filled by applying putty and then painted.

4　The strain insulator string must be securely fixed.The strain insulator string of the same phase shall have even tensile force.The grading ring shall be installed horizontally，without any inclination.The discharge counters shall be installed at a consistent position，well-sealed，properly connected，and grounded securely.

5　The safety device for rupture disc of metal oxide arrester shall be in good condition.The gas exhaust channel shall be unblocked，and the exhaust gas shall not cause phase-to-phase flashover or flashover to earth.

6　Installation of expulsion-type arrester:it shall be fixed at the closed end of the tube，with the open end facing down.Where it is installed in an inclined way，the included angle shall not be less than 15°.For non-freewheeling arrester，the included angle shall not be less than 45°.

7　Installation of air terminations:the preparation of the electrode of air terminations shall be in accordance with the design requirement，the electrode made of iron shall be galvanized.The included angle between the axial line of air terminations and the axial line of lightning arrester tube shall not be less than 45°.The air terminations should be installed horizontally，and its gap distance shall be in accordance with design requirements.

5.2.6　The installation of capacitors shall be in accordance with the following requirements:

1　When the power capacitors are installed in groups，the difference between the three-phase capacitances should be adjusted to the minimum.The difference between the maximum and the minimum shall not exceed 5% of the mean capacitance of three phases.If there are design requirements，they shall be met.

2　The capacitor frame shall be kept at the proper horizontal and vertical positions and shall be securely fastened，and its paint shall be complete.The capacitors shall be arranged in such a way that the nameplates face the passage，and they shall have a serial number.

3　The connection of capacitor terminals shall be symmetrical and neat in accordance with design requirements.The bus and branch lines shall be marked with respective phase color.

4　Where the coupling capacitor is installed，the fastened bolts on its top cover shall not be loosened.The terminal of the lead wire connected to the capacitor shall not be subject to a transverse tensile force.