Index:

• Installation procedure
• Available adapters
  • Voltage TAP
  • Test TAP
• Possible issues with the installation of the TAP adapter
  • Water or moisture inlet:
  • Oil leakage prior to the installation
  • Signs of cable welding in the connection pin of the TAP
• Observations
  • Installation precautions 
• Bushing Testing

The following procedure indicates the most common ways for the mechanical installation of Treetech TAP adapters.

The existence of several models of Capacitive TAPs on high-voltage bushings indicates the necessity of different models of TAP adapters for bushing monitoring installation.

The installation of the adapters must mainly respect the mechanical construction of each bushing. There are two models of TAPs available:

• Voltage TAP: these, normally more robust, may present a higher resistance to threading. We do not indicate to use of tools for threading unless extremely necessary.

• Test TAP: these, ordinarily less robust, can be threaded more easily. We do not recommend the use of tools for tightening the TAP adapters.

Installation procedure

The installation procedure for the TAP adapters should follow the steps below: 

1. Removing the TAP grounding cap: You must take care when removing the TAP cap, as old bushings may be too tight. In these cases, it may be necessary to use appropriate tools for its removals, such as a fixed open-end wrench or adjustable spanner. If a utensil is required, you should note that high torques can damage the TAP of the bush when this is not robust. In some cases, another wrench may be necessary to support the TAP (an example of TAP is shown in Figure 3 below);
2. Cleaning of the capacitive TAP thread for adapter installation: preferably using a steel brush, but you can also use a cloth, sponge, or similar materials, to ensure complete removal of residues such as iron filings, contaminated grease, solder tin, paint, rust, et cetera;
3. Check the measuring connection pin/point of the TAP adapter: It should be clean and free of obstructions such as iron filings, solder tin, paint, and rust, among others. If necessary, you should clean, and it may be required to use abrasive material such as heavy duty scour pad or sandpaper to remove imperfections; 
4. Adapter thread testing: this should install without the use of tools. In cases where the TAPs are robust, it may be necessary to use a greater force to thread the adapter. If the use of tools is demanded, these must respect the construction of the TAP in question to avoid overtightening;
5. Testing the electrical connection of the adaptor: Firstly, the mechanical connection of the contacts is tested by marking the connection pin with a projector pen or pencil, and the proper connection is verified (by removing the ink from the initial marking). Additionally, it can measure the leakage current by injecting voltage into the bushing. Alternatively, the capacitance can be measured using a multimeter. It is worth noting that this measurement will not be close to the actual capacitance of the bushing.
6. Connection of the adapter plug: The plug should be connected and installed according to the BM bushing monitor manual.

Available adapters

The following are indications of existing TAPs and recommended care during the installation of TAP adapters.

Voltage TAP

There are several models of voltage TAP with different levels of robustness, represented in the photos below. It is not recommended the use tools for threading unless it is necessary to guarantee electrical contact and sealing.

 Figure 2 – More robust TAP built into the bushing base.

On the following TAP, less robust construction, no tool should be used to install the adapter, as the TAP may rotate, causing leakage or moisture ingress.

Figure 3 – Voltage TAP (with cover) with less robust construction.

Figure 4 – Voltage TAP (without cover) with less robust construction.

Test TAP

There are several models of test TAP. Below is an indication of some of the models. In general, test TAPs are not robust, but there are exceptions. We do not recommend the use of tools for threading.

Figure 8 - Test TAP. Although it is robust as it is attached to the base of the bushing, it is not recommended that tools are used for installation.

Possible issues with the installation of the TAP adapter

Water or moisture inlet

It’s quite common to occur the inlet of water or moisture in TAPs, making the installation of the adapters difficult. In cases like this, as informed above, the thread of the capacitive TAP must be cleaned in the best way possible. In some cases, a male or cosinet must be used to remake the thread of the capacitive TAP.

 Warning !

Treetech is not authorized to structurally intervene in field equipment, being in this case responsability of the customer.

Figure 9 – TAP showing signs of water inlet. The thread looks damaged by oxidation.

Oil leakage prior to the installation

In some cases the capacitive TAPs already shows oil leakage prior to the installation of the TAP adapter, so it's recommended the repairing or substitution of the of the TAP or the bush. It’s not recommended the installation of the TAP adapter if oil leakage is detected.

 Warning !

If the installation is authorized under these conditions by the customer, they assume the responsability of the installation.

Figure 10 - TAP with signs of leakage prior to the installation of the TAP adapter.

Signs of cable welding in the connection pin of the TAP

In some cases, the capacitive TAPs shows signs of welding in the pin of the TAP. This welding must be removed in the best possible way to allow the installation of the adapter . In cases of imperfections which interfere in the connection of the adapter, it may be necessary the usage of abrasive materials, such as heavy duty scour pad or sandpaper.

 Warning !

In cases like this, the issue is presented to the customer, who is the one responsible for the repair.

Observations

The Treetech TAP adapter is designed for applications in the most severe weather conditions, tested and approved in thousands of applications worldwide.

Installation precautions 

• Screw on by hand, without the aid of tools. 

• Do not lean, step on or hang objects on the tap adapter. Always anchor the cable or conduit in a nearby structure to relieve mechanical stress on the plug.

Bushing Testing

It is necessary to remove the TAP adapter to connect the TAP to the BM-MM to perform tests on the bushings. To do this, once it has been verified that there is no voltage on the bushing (transformer disconnected), disconnect the plug cable from the TAP adapter, as shown in the Figure below. Then disconnect the TAP adapter taking the same precautions as mentioned above, according to the type of TAP.

Once the tests have been carried out (according to the manual for the bushing and the manufacturer's guidelines), follow the same installation precautions previously mentioned to put the equipment back into operation.

Also, check out:

Possible Problems Installing TAP Adapters

If you have any problems or difficulties with the procedure, please do not hesitate to contact us!

Contacts:
Telephone: +55 (11) 2410 – 1190 — Ext. 425
Cellular: +55 (11) 97225 – 8683 - WhatsApp
E-mail: sac@treetech.com.br
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