HR roles will be a referee on appraisal in terms of HR performance management?

Yes, but not all cases, the role of supporting more than one role to impose laws because human resources management is to support the management and governance of the company and the employee and work to build confidence between them so the laws to achieve the goals in accordance with the criteria to be determined by the company evaluated either to monitor the performance of the employee to achieve goals and processing drifts that be possible or not as the case may be

In Performance Appraisal Score Sheet there must be part of skills, knowledge, improvement of works to be justified by the Department Head of the Employees and a part of HRM should be there for the attendance, behavior, grievance and discipline.

To be impartial in assessment will depend on the capabilities and attitude of the HR Department  and the management's intention and directions. The framing of Hr policies, appraisal methods, employees attitude towards HR and the Organization all that matters in the appraisal and have influence.