"Unable to load DLL 'OraOps12.dll' Access is denied. " in the normal mode powershell console

I use Oracle.DataAccess.Client in Powershell to access Oracle database.

New-Object -TypeName Oracle.DataAccess.Client.OracleConnection($connstring)

If I run this script in an Administrator mode console, it works very well.

But if I run the script in the normal mode console, I get this error

"Exception calling ".ctor" with "0" argument(s): "The type initializer for'Oracle.DataAccess.Client.OracleConnection' threw an exception."

The inner exceptions, and statcktrace:

"Unable to load DLL 'OraOps12.dll': Access is denied. (Exception from HRESULT: 0x80070005 
(E_ACCESSDENIED))" 

   at Oracle.DataAccess.Client.OpsInit.CheckVersionCompatibility(String version)
   at Oracle.DataAccess.Client.OracleInit.Initialize()
   at Oracle.DataAccess.Client.OracleConnection..cctor()

I have assgined the user the full control to Oraops12.dll, why I still get this error? What do I miss?