You access an IProtocols object by calling the IBuildCatalog.Protocols property, as in the following example, where objProtocols is the name you give to the IProtocols object:
Option Explicit
On Error Resume Next
Dim objSearchAdmin, objBuildServer, objCatalogs, objCatalog, objProtocols, objProtocol
Set objSearchAdmin = CreateObject("Search.SearchAdmin.1")
Set objBuildServer = objSearchAdmin.BuildServer
Set objCatalogs = objBuildServer.BuildCatalogs
For Each objCatalog in objCatalogs
Set objProtocols = objCatalog.objProtocols
Wscript.Echo objCatalog.Name & " searches the following protocols:"
For Each objProtocol in objProtocols
If objProtocol.Included Then Wscript.Echo objProtocol.Urlname
Next
Next
'Release objects
Set objProtocols = Nothing
Set objCatalogs = Nothing
Set objBuildServer = Nothing
Set objSearchAdmin = Nothing