en opción Seleccionar cómo hacer uno predeterminado en Angular
<option [ngValue]="undefined" selected>Select</option>
Fancy Fly
<option [ngValue]="undefined" selected>Select</option>
<h3>AngularJs ng-options to Set Default Value</h3>
<select name="users" ng-options="user.name for user in arrlist" ng-model="userselected">
<option value="">--Select User--</option>
</select><br /><br />