using (PowerShell PowerShellInstance = PowerShell.Create())
{
    string query = string.Format(@"$server = ""{0}""
        $db = ""master""
        $sql = ""SELECT DISTINCT hostprocess FROM master.dbo.sysprocesses WHERE last_batch <  DATEADD(MINUTE, -30, GETDATE()) ""
        $user = ""{1}""
        $pass = ""{2}""
        $processId = Invoke-sqlcmd -Server $server -Database $db -Username $user -Password $pass -Query $sql | select -ExpandProperty hostprocess
        Write-Output $processId", Server, DbUserName, DbPass);
    PowerShellInstance.AddScript(query);
    var results = PowerShellInstance.Invoke();
}