ON-LINE PARTIAL DISCHARGE CONDITION MONITORING OF COMPLETE NETWORKS FOR THE PULP AND PAPER INDUSTRY: CHALLENGES AND SOLUTIONS EXPLAINED THROUGH CASE STUDIES Lewis Dodd Member, IEEE HVPD Ltd Manchester, UK Riccardo Giussani Member, IEEE HVPD Ltd Manchester, UK Aaron McPhee Member, IEEE International Paper Augusta, GA, USA Andrew Burgess Member, IEEE PDMSGlobal LLC Houston, TX, USA Abstract - Outages within the paper industry lead to significant costs to operators. To reduce unplanned outage and losses condition monitoring (CM) techniques can be implemented to determine asset health and help target maintenance where it is most required. The challenges faced by the paper industry to implement condition based maintenance (CBM) on their medium voltage (MV) and high voltage (HV) networks and solutions for on-line partial discharge (OLPD) monitoring are due to the range and number of assets present and geographical spread coupled with problems of retrofitting the technology on pre-existing plants. The implementation of OLPD testing and/or monitoring can vary based on several factors: network topology, connected assets, switchboard type, owner budget and owner’s desired local engineer involvement. This paper discusses different approaches to implementing an OLPD test program, ranging from simple handheld survey units to complete network monitoring. This paper focuses on case studies of the deployment of OLPD testing and monitoring solutions at several paper sites within the U.S. The case studies will present diagnostic testing of unshielded MV cable at one paper mill up to full permanent OLPD monitoring systems at two others. Index Terms – Complete Network Monitoring, HFCT, HV Assets, HV motor, HV generator, HV transformer, Pulp and Paper, OLPD, On-line Partial Discharge, Remote OLPD Monitoring I. NOMENCLATURE AA ultrasonic Airborne Acoustic, a PD sensor. CBM Condition Based Maintenance. CM Condition Monitoring. CT Measurement Current Transformer. HFCT High Frequency Current Transformer, a PD Sensor. HV High Voltage. MCSA Motor current Signature analysis. MV Medium Voltage. OLPD On-line Partial Discharge. PD Partial Discharge. PDMS Partial Discharge Monitoring Server. SCADA Supervisory Control and Data Acquisition. TOF Time of Flight. TEV Transient Earth Voltage, a PD Sensor. XLPE Cross-Linked Polyethylene Insulation. II. THE PULP AND PAPER INDUSTRY The pulp and paper industry is the fourth largest industrial energy consumer globally, after iron and steel, chemicals, and non-metallic minerals [1], [2]. Pulp and paper production requires heat and electricity as the primary source of energy input with energy costs making up, on average, 16% of production costs [3]. Therefore, rising energy costs are a concern for the industry and the need to maintain the production assists free of electrical/mechanical failures is of primary significance to maximize the plant efficiency. North America continues to remain the largest world region for paper consumption and enjoys significant fiber resources to support this. The main inputs for paper and paperboard are different forms of pulp, which in turn are made from wood or other raw materials containing cellulose fibers. If a pulp and paper mill produces the pulp on-site for use in the production of paper products it is considered to be an integrated mill. Conversely, if the pulp is dried and pressed before transportation to the paper mill for production it is considered to be a separated mill. The following sections will explore the different methods of producing the pulp required for the paper industry. A. Mechanical Pulping Mechanical pulping is principally used in integrated pulp and paper mills rather than separated mills. This process uses mechanical energy to separate the fibers. The efficiency of this process can vary from 1 – 45% with respect to the raw materials used, however, the process is considered both simple and efficient with the primary disadvantage being that the wood fibers are often damaged [4]. Mechanical pulping is mainly used for weaker paper such as newspaper, printing paper, toweling, tissue, or paperboard. Where additional strength is required, chemical pulp is occasionally mixed in to the process. Electricity is the main source of power for mechanical pulping [5] and mechanical pulp production yields substantial amounts of heat as side product, which can be used for district heating [6], [7]. B. Chemical Pulping Both integrated and non-integrated pulp and paper mills can make use of chemical pulping. Chemical pulping involves removing the cellulose wood components from the pulp whilst