AVX. Operation and Maintenance Manual AVX 1200A A 15kV to 362kV. ALUMINIUM VERTICAL BREAK DISCONNECT SWITCH 15kV to 362kV 1200A A

Transcription

1 Operation and Maintenance Manual AVX AVX AVX KV-E R00 1

2 TABLE OF CONTENTS 1 General Description General Contacts Switch Base Insulator Stack Bearing Assemblies Terminal Pads Grading Rings Nameplates Shipment and Storage Shipment Inspection Storage Mounting and Adjustments Operating Instructions Torsion Handle Operation Pump Handle Operation Manual Handwheel Operation Manual Worm-gear Operation Motor Operation Maintenance, Lubrication and Inspection Maintenance Recommendations Recommended Spare Parts Blade Contact Strip Replacement Instruction Contact Fingers Replacement Instruction AVX KV-E R00 2

3 REVISION TABLE REVISION R00 DESCRIPTION OF CHANGE FIRST ISSUE AVX KV-E R00 3

4 1 General Description 1.1 General The MindCore Technologies Type AVX is an aluminum vertical break switch having three insulator columns, one of which rotates the switch. Principal components of the operating mechanism are shown in the accompanying illustrations. Figure 1 - General Arrangement for AVX The operating crank turns through an angle of 99 on horizontally mounted switches to open or close the switch. About 2/3 of this rotation is required for raising or lowering the blade. The remaining rotation is used in rolling the blade about its longitudinal axis to make or break electrical contact. The roll angle varies slightly but is near 90. Use of large roll angle permits easy entry of the blade into the jaw under icing conditions. Because the operating crank travels through a large angle during the blade rolling sequence, geometric considerations dictate that some system dimensions are allowed to vary to accommodate the circular arm motion. This variation is achieved by permitting the length of the drive stud to vary and returns using a spring. A stopper on the opposite side of the fork lever limits the travel and prevents unwanted behavior of the mechanism. The blade of an upright mounted switch open through an angle of 97 so that gravity assists in holding the switch in the open position. All pressure is thus removed from the inter-phase linkage so that it can be safely disconnected for adjustment. A stop bolt within the live part frame is factory set to conform to this angle. AVX KV-E R00 4

5 1.2 Contacts On each side of the blade, current transfer is through copper strips bolted to the blade assembly using stainless steel hardware. The contact surface is full round edge which provides a rotational adjustment tolerance of ± 5. The contact surfaces of both copper elements are silver-brazed. The copper is tinned on surfaces adjacent to aluminum and oxide inhibitor is brushed into the aluminum during assembly. Belleville washers are employed to maintain a satisfactory electrical connection during thermal cycling. Contact fingers at both the jaw and hinge ends are of silver-brazed hard drawn copper. Their "reverse loop" configuration exploits the magnetic field generated by short circuit currents to provide increased contact pressure under fault conditions. Normal contact pressure is maintained by nylon-insulated stainless steel coil springs. This pressure is achieved when the contact fingers are deflected approximately 1/8" [3mm] giving a visual check that satisfactory contact has been achieved. Positive mechanical stops are featured in the jaw assembly to correctly position the blade. An aluminum stop limits downward blade travel. A latch is used to firmly secure the contact in the jaw. 1.3 Switch Base Bases are supplied designed to suit the application. Bases are manufactured by break-forming 1/4" [6mm] steel plate into a "top-hat" profile. Where more robust bases are required, welded gussets are added for additional rigidity. And for the most demanding applications, structural C-channels with welded gussets are used. Each base is supplied with grounding holes NEMA type. Grounding connector can be supplied on demand. Refer to the project specific control and mounting arrangement drawing for details. 1.4 Insulator Stack Bearing Assemblies The bearings employed are for 3" [76mm] and 5" [127mm] bolt circle (B.C.) applications. These bearings are of the lifetime greased, double lip sealed type and are fully maintenance free. In addition, each bearing are supplied with adjustable stoppers (in both open and closed positions). AVX KV-E R00 5

6 1.5 Terminal Pads Type AVX switches rated at 1200A and 2000A employ 4 bolts NEMA pads, which is 9/16" [14.5mm] diameter holes on a 1 ¾ x 1 ¾ [44mm x 44mm] square configuration. All ratings have 2 additional 4 bolts NEMA terminal pads at 90 o on either side of the main pad. All terminal pads are made of aluminum. 1.6 Grading Rings Grading rings can be mounted on the AVX switch if necessary. Grading rings are normally shipped assembled in factory. 1.7 Nameplates Nameplates are fastened to the control handle support plate as well as to each switch base. Figure 2 - Typical Layout of Nameplate AVX KV-E R00 6

7 2 Shipment and Storage 2.1 Shipment MindCore Technologies switches and equipment are usually shipped in crates of parts, and assembled or partly assembled (less insulator) switch phases. Motorised drive mechanisms are shipped crated and all drive pipes are shipped in bundles. Upon delivery, each crate should be inspected for damage prior to unpacking, and preferably before removal from the transport truck. If there is visible loss or damage, notify the truck driver immediately and ask for a carrier inspection. Note condition of the shipment on all copies of the delivery receipt. File a claim with the carrier and notify MindCore immediately. 2.2 Inspection Uncrate the switch assembly and check for damage. Operate the switch to check for free operation. However do not change any of the factory settings for closed and open positions of the switch bearing stops. Each switch can be hand operated. If there has been concealed damage from transit, please notify the trucking company within 15 days of receipt of the shipment, and ask for a carrier inspection. File a claim with the carrier and notify MindCore Technologies immediately. 2.3 Storage Parts boxes and motor drive mechanisms should be stored in a heated or unheated indoor storage area. Switch phases and drive pipes may be stored outdoors but should be in a sheltered storage area. AVX KV-E R00 7

8 3 Mounting and Adjustments Step 3.1 Study the installation drawings, identify all parts and validate mounting holes. Make sure to follow installation plan. Please note that the MindCore Technologies AVX switches are factory adjusted for correct and consistent operation. Any readjustments on the current carrying parts (above insulators) can result in malfunction or damage to the switch. If the switch was delivered on its insulators, advance to step 3.9 Step 3.2 Step 3.3 Step 3.4 Step 3.5 Step 3.6 Unbolt and remove current carrying parts from the preassembled pedestals, switch bearings and bases. Assemble the insulator stacks as required for 2 or 3 pieces insulators on the switch bases. Verify that the insulators are in a straight line. This can be checked by running a string from the top of the jaw insulator to the rotating insulator at the other end. Verify that the insulators are vertical through the use of a plumb line. Turn the rotating insulator to check for wobble. An eccentricity of more than 1/8" [3mm] must be removed by exchanging insulators or by adding shims. Jacking bolts are provided to permit height and tilt adjustments. Correct alignment of insulators is critical to proper switch operation. Mount the jaw assembly on the correct insulator using hardware specified into the installation drawing. Leave the bolts finger tight as more adjustment will be required later on. Hoist the hinge side of the switch into position using a nylon sling attached to the blade just ahead of the blade lever. Attach a rope to the blade contact so that the switch can be guided into position from the ground. Bolt the hinge side of the switch using the hardware specified on the installation drawing. Ensure that the blade contact is centered in the jaw and the crank flange on the rotating insulator column before tightening the bolts. It may be necessary to rotate insulator units if frame bolt holes slack is inadequate to complete alignment. AVX KV-E R00 8

9 Step 3.7 Step 3.8 Step 3.9 Step 3.10 Step 3.11 Step 3.12 Bolt the crank flange to the top of the rotating insulator stack. Do not use this connection to force a poorly aligned insulator into position as subsequent binding in the upper and lower bearings will result in excessive switch operating force and possibly insulator breakage. Check blade alignment by lowering it into the jaw. The blade contact should be centered into the jaw. Tight the insulator bolts on the jaw assembly when everything is adjusted properly. Hoist all three phases to their respective place on structure (as shown on the installation drawing). When bolting the switch bases to the structure, be sure that all mounting surfaces are flat between them. Install 3 of 4 mounting bolts and observe if there is a gap between the switch base and the structure at the fourth bolt. If yes, put a shim to fill this gap. By doing this, we want to avoid twisting the switch base frame and keep the switch adjustment optimal. Mount all the operating mechanism parts except the inter-phase pipes in the locations shown on the application layout drawing. Set the adjustable lever on top of the gear reducer or on outboard bearing to the length and angle shown on the installation drawing (set in closed position). If switch is motor operated, use motor drive to put the operator in closed position. Make sure that the operator is free running from the vertical pipe. Also, validate that the motor operator turns on the appropriate side when opening. If the switch is manual operated, put the manual operator in closed position. Refer to your installation drawing for open/closed positions and rotation of the vertical pipe. Then tighten the pipe coupling between operator output shaft and vertical drive pipe. AVX KV-E R00 9

10 Step 3.13 Step 3.14 Step 3.15 With the first driven phase in the closed position, connect the main drive pipe (reach rod) between that phase and the gear reducer lever (or outboard bearing lever). Note that the lever should be slightly over centre with respect to the pipe (to obtain the over toggle type action). IMPORTANT: Do not use the motor drive (if switch is so equipped) until the switch is fully adjusted. Use manual mode only during adjustment. Open the first driven phase. If the switch does not open fully, return it to the closed position and lengthen the lever on gear reducer (or outboard bearing). The main drive pipe length will also have to be altered. If the switch reaches the fully open position before the gear reducer lever has travelled over centre, return to the closed position and shorten slightly the gear reducer lever (or outboard bearing lever). Again, the main drive pipe length will also have to be altered. Position the switches (all 3 phases) in closed position. With all three phases so positioned, connect the inter-phase pipe links. Adjust the pipe lengths until all three phases operate in synchronism. Please note that MindCore Technologies switches are factory adjusted to eliminate the need for field adjustments. If difficulty is experienced in setting up the three phase unit, please note the following: Blade contacts will tolerate up to +5 o of rotational misalignment in closed position. Perfect synchronisation is not essential to switch operation. Structure and insulator deflection will always produce some loss of synchronisation. IMPORTANT: Instructions for the motor drive mechanism can be found elsewhere in this manual. AVX KV-E R00 10

11 Tightening References With the exception of certain adjustment bolts, Table 1 torque values apply to all bolts on the AVX. For copper contacts with Belleville washers, use Table 2. Table 1 Torque Bolt Size Torque Value Required 3/ Nm (18 22 ft-lbs) 1/ Nm (55 62 ft-lbs) 5/ Nm (75 80 ft-lbs) Table 2 - Torque to use with Belleville washer Bolt Size Torque Value Required 1/4-20 (2 layers of #4L42301) 8 Nm (6 ft-lbs) 3/8-16 (#6L61301) 13.5 Nm (10 ft-lbs) 3/8-16 (2 layers of #6L61301) 27 Nm (20 ft-lbs) 3/8-16 (#1755-2) 19 Nm (14 ft-lbs) 3/8-16 (2 layers of #1755-2) 37 Nm (28 ft-lbs) 1/2-13 (#680833) 28 Nm (21 ft-lbs) AVX KV-E R00 11

12 4 Operating Instructions Operating limits of the AVX switch mechanically and electrically are defined on the control and mounting arrangement drawing found elsewhere in this manual (see table of contents). 4.1 Torsion Handle Operation AVX switches can be operated using a torsion handle assembly. All torsion handles are equipped with the provision for padlocking in either the open or closed positions (padlock not included). To operate, remove the padlock and swing the handle to the horizontal position. Rotate the handle from one stop to the other stop. Try to use a uniform speed of rotation avoiding jerky starts and stops. Lower the handle into the opposite stop and padlock. 4.2 Pump Handle Operation AVX switches can be operated manually with a pump handle assembly. All pump handle assemblies are equipped with a provision for padlocking the operating mechanism. To operate the switch, remove the padlock and locking pin (if so equipped padlock by others). Lower or raise the handle to either open or close the switch. Try to use a uniform speed of rotation avoiding jerky starts and stops during the opening and closing process. Replace the pin and padlock when finished. 4.3 Manual Handwheel Operation AVX switches can be operated manually with a handwheel assembly through a 9:1 ratio gear reduction unit. Handwheel assemblies are equipped with a provision for padlocking the operating mechanism. To operate, remove the padlock and locking pin (if so equipped padlock by others). Rotate the handwheel in the direction indicated on the handwheel casting itself to either open or close the switch. Try to use a uniform speed of rotation avoiding jerky starts and stops during the opening and closing process. Replace the pin and padlock when finished. 4.4 Manual Worm-gear Operation AVX switches can be operated manually with a 40:1 ratio worm gear manual operator. All worm-gear operators are equipped with a provision for padlocking the operating mechanism. To operate, remove the padlock (if so equipped padlock by others). Turn the hand-crank clockwise or counter-clockwise to either open or close the switch. Replace the padlock when finished. 4.5 Motor Operation AVX switches can optionally be equipped with a motor drive mechanism, which allows for both local or remote switch operation, as well as fully manual operation. For details on motorised operation of the switches, please refer to the MindCore type MSO manual. AVX KV-E R00 12

13 5 Maintenance, Lubrication and Inspection An air switch is not equipped with isolating switches to allow it to be serviced at frequent intervals. This does not indicate, however, that an air switch requires no care or inspection. The frequency of inspections will necessarily be a function of the atmospheric conditions at a given switch location and frequency of operation. MindCore Technologies switches are designed to require a minimum of maintenance. All switch bearings are permanently lubricated. Pivot points generally incorporate "Oilite" bushings which do not require lubrication. The electrical contacts, being exposed to the elements, are the primary items requiring periodic inspection. Ideally, an annual check is desirable. However, this is often impractical. The user must establish a reasonable compromise in service and maintenance requirements taking local atmospheric conditions into account. Experience shows that a switch which has been in service for some time will generally run warmer than a new switch. Normally, a simple open/close operation of the switch will wipe the contacts clean and reduce operating temperatures. 5.1 Maintenance Recommendations Make sure that the switch is disconnected from all electrical power before servicing. After power has been disconnected from the switch, ground leads or their equivalent should be attached to both sides of the switch. Clean the insulators where abnormal conditions, such as salt deposits, cement dust or acid fumes prevail, to avoid flashover as a result of the accumulation of foreign substances on their surfaces. Examine and check the contacts to ensure that they are aligned and that contact surfaces bear with a firm, uniform pressure. Check the contact surfaces. If it is known that the switch has been subjected to short circuit conditions, efforts should be made to inspect that switch at the earliest opportunity. This is especially important if the switch contacts are corroded. If the switch has been damaged, its ability to withstand a second fault may be impaired. Look for burning or pitting of the contacts, annealing of the fingers and melting of the nylon backup spring bushings. Replace any pitted or burned contacts. If the pitting is of a minor nature, smooth the surface down with clean fine sandpaper (not emery). All contact surfaces on blades and jaw contacts are to be lubricated with good low temperature grease such as "Molykote BG-20". However badly damaged contacts should be replaced. If the nylon backup AVX KV-E R00 13

14 spring bushings are burned, the contact springs themselves are suspect and should be replaced. Inspect that bolts, nuts, washers, cotter pins and terminal connections are in place and tight. If the switch is gang operated, inter-phase linkages, line operating parts, rods, levers and bearings should be cleaned and lubricated as required. Check for simultaneous closing of all blades and for complete contact in the closed position. When the switch cannot be disconnected from power, hot stick servicing may be used to as great as an extent as possible. Where periodic maintenance of any kind is not possible, it should be recognized that the life of the switch contacts may be affected. In these cases, when a switch operation is made, it is recommended that the switch be opened and closed several times instead of just once in order to clean the contacts more effectively. In supplement to the above, MindCore Technologies recommends that where lubrication is necessary, such as inter-phase linkages, clevis pins, operating pipe guide bearings, rods and levers, a lubricant such as "Molykote BG-20" be used. As mentioned above, switch bearings are completely sealed and require no lubrication. AVX KV-E R00 14

15 5.2 Recommended Spare Parts Please note that all contacts on the switch are easily fielded replaceable. Listed below are recommended replacement parts for single phase only. Please triple quantities when ordering parts for a three phase switch. PART DESCRIPTION AVX 1200A AVX 2000A PART NO. QTY. PART NO. QTY. Contact Finger Silver Inlay Hinge Contact Finger Coil Spring Nylon Insulating Bushing MC MC Belleville Washer 3/8" SS Internal Tooth Washer 3/8" SS Contact Finger Silver Inlay MC MC Jaw Contact Finger Coil Spring Nylon Insulating Bushing MC MC Belleville Washer 3/8" SS Internal Tooth Washer 3/8" SS Hinge Contact Strip Jaw Contact Strip Contact Strip Silver Inlay MC MC Belleville Washer 1/4" SS 4L L Contact Strip Silver Inlay MC MC Belleville Washer 1/4" SS 4L L Arcing Horn Assembly (15kV to 170kV) MC MC Arcing Horn Assembly (230kV to 362kV) MC MC AVX KV-E R00 15

16 5.2.1 Blade Contact Strip Replacement Instruction A. Remove all bolts and Belleville washers. B. Remove contact strip. C. Use fine emery paper on aluminum surface, clean and coat with "Penetrox A" inhibitor. D. Replace contact strip on blade. Align contact element carefully. E. Replace 6 bolts and Belleville washers. Torque bolts to 6 ft-lbs (8 Nm). Figure 3 - Exploded View of Blade Contact Strip AVX KV-E R00 16

17 5.2.2 Contact Fingers Replacement Instruction A. Remove all bolts and washers of each contact fingers. Then, remove the contact fingers. B. Ensure that inhibitor is wire brushed into aluminum surfaces before installing new fingers. C. Mount coil spring and internal tooth washer on nylon insulating bushing. D. Insert the sub-assembly into the contact finger aligned with upper hole. E. Mount each finger sub-assembly on each side. F. Torque mounting bolts to 19 ft-lbs (19 Nm). Figure 4 - Isometric View Figure 5 Section View Figure 6 Exploded View of Contact Finger AVX KV-E R00 17