Today's industrialized world requires more power generation that can be produced by renewable distributed energy resources (DERs) to minimize air pollution. Major DERs integrated into the grid today include solar farms, windmill farms, and biogas. Common DERs (energy shift renewables) providing power inside major ports include hydrogen (H-2) and liquefied natural gas (LNG). The authors are working with the Port of Long Beach (POLB), CA, USA, which has implemented H-2 and LNG. During fault conditions, the grid faces the challenge of applying fast fault clearing protection relay schemes capable of providing secure control and communication signals to avoid tripping the power supply to large customers, such as ports. This article introduces the current state of networked controllers called microgrid controllers. Such controllers can provide fast control and communication signals to nearby grid substations and 24/7 control centers to manage power outages. Without these controllers, power outages can affect a port's service continuity, affecting the port's cold-ironing operations (CIOs). The article includes types of studies required by a port to work with a utility for a smooth energy shift to renewable integration for the mutual benefit of the utility and the port. This shift will contribute to meeting the net-zero air pollution goal by 2050.

The integration of renewable energy resources, a step forward for decarbonization, has posed trivial power system protection and reliability challenge for power supply to I&CPS facilities. Such switching surges and power system harmonics generated by the power electronics used by the renewable energy resources. Severe weather changes, extreme heat, across the insulators, lightning thunderstorms breaking overhead bare line conductors falling on ground to cause fire endangering safety of public and animals. Severe lightning and switching surges injecting additional harmonics to harmonics from renewable energy resources integrated into the grid, makes power system protection at the PCC challenging. This paper reviews application of power system surge arresters, insulators, surge limiters, protection of wood poles from fire by insulators flashover to poles metallic support structure. IEEE and IEC standards on surge arresters and insulators are included to establish difference of these devices' selection methods. This paper ends with practical application recommendations of surge protection devices based upon power system equipment configuration, insulation level, and surge propagation theory

This article describes the cause of an arc fault in the cable compartment of a medium-voltage arc-resistant metal-clad switchgear (MV ARMCS) integrated inside an outdoor enclosure. The manufacturer of the outdoor enclosure for the switchgear was not the manufacturer of the arc-resistant switchgear. The arc fault occurred when there was no operator inside the switchgear to initiate the fault. The arc fault on a sunny day occurred without any evidence of a power system switching surge and without maintenance personnel touching the switchgear. The issue of missing hinged flaps is discussed in this article. An analysis of fault recordings captured by the digital protection package establishes that the arcing fault generated arc fumes with pressure that were exhausted automatically by the arc exhaust chamber assembly out of the switchgear through a wall-mounted louver. After the arc fault incident, the maintenance crew along with technical staff noted that cable insulation damage occurred due to outside moist corrosive air entering the cable compartment. Every time the wall-mounted louver opened and closed with a wind draft, air would become trapped and reach the cable compartment. Without a hinged flap at the top of the cable compartment, moist corrosive air degraded the cable insulation, causing the arc. This article provides recommendations and conclusions to avoid such incidents in the future in arc-resistant switchgears.

The authors are experienced in the design, installation, testing, safety of personnel, and commissioning of shore power projects, "connection/disconnection of ships to shore power during berthing at ports." Herein, the authors provide their views of some of the issues that may require first-hand input to the industry professionals involved in these types of projects. Technical references and recommendations included in the article should enhance the reader's knowledge of shore power projects mandated in numerous regions around the world at larger ports to enhance safety of operators, minimize air pollution in the vicinity of ports for health benefits, and produce a cleaner environment for the pubic.

The integration of renewable energy resources, a step forward for decarbonization, has posed a power system protection and reliability challenge. Such challenge is switching surges and power system harmonics generated by the power electronics of renewable energy resources. Severe weather changes, switching surges, harmonics, and lightning surges cause electrical insulation failure which leads to unpredictable equipment hazards and electrical safety threats. This paper reviews application of power system surge arresters, insulators, surge limiters to mitigate power system insulation failure by diverting surge energy to earth. Application of ac and dc surge protection devices for industrial projects using grid power with renewable energy resources is included in this paper. Tables of current IEEE and IEC standards on surge arresters and insulators are included to establish difference of these devices’ selection methods. A design approach for appropriate selection and application of surge protection devices for electrical insulation protection, normally used equipment insulation coordination with margin of protection is included. Transient surge voltages and associated surge currents containing damaging transient surge energy obeys surge propagation laws using theory of surge reflection, surge refraction, surge impedance, requiring distributed inductance and capacitance parameters as if the surge is travelling long distance on overhead lines and underground cables within the facility. Surge propagation theory is known to industry long before the current software analysis of electromagnetic transients (EMT) used by engineers to model accurately power electronic devices and surge arresters for selection of adequately rated surge protection devices. This paper ends with practical application recommendations of surge protection devices based upon power system equipment configuration, insulation level, and surge propagation theory.

Certain electrical fire events that have occurred in the last 2 years in California and other parts of the world have led us to consider using underground cables instead of more hazardous overhead bare distribution/transmission lines. This would minimize fire and life safety hazards that have occurred from broken live conductor falling on dry grass and trees. Techniques for bonding underground cable shield/sheath (S/S) to ground to minimize circulating current in S/S are included in IEEE Guide 575–2014 [1]. This guide suggests applying surge voltage limiters (SVLs) to ground S/S at one end of each section of underground cable. Such a grounding technique stops circulating current through S/S during normal load flow current as SLVs will not be conducting, they will conduct only under transient surge current flow through the cable to release the induced surge current on S/S to ground to protect S/S from damage. Medium-voltage (MV) cable protection from lightning and switching surges at overhead to underground locations remain the same when SVLs are applied at S/S of the cable sections. This paper discusses selection criteria for SVLs based on the underground cable voltage, cable parameters, suppliers' cable specifications, and published test data regarding SVLs' capability to mitigate expected surges without damage to S/S or the SVLs.

IEC/IEEE Joint Working group (WG) members, under the leadership and guidance of the convener, put forward a tremendous effort to compose standards. Many meetings take place for consensus resolutions of the review comments. Authors of this paper are IEEE officers and WG members of this standard from the first issue through the present revised version and have knowledge of the history of comments and their resolution through the consensus process. This paper clarifies some of the requirements for the proper application of the standard. Authors are experienced in the design, installation, testing, and commissioning of shore power projects and provide their views of some of the issues that may require first-hand input to the industry professionals involved in these types of projects. Technical references and recommendations included in the paper should enhance reader’s knowledge of shore power projects mandated in numerous regions around the world to enhance safety of operators, minimize air pollution in the vicinity of Ports for health benefits and produce a cleaner environment for the public.

Shore Power Transformers are used to connect berthing ships at ports to use shore power from the port facilities. It has been established that using shore power instead of power from on-board generators can minimize air pollution as ships use low-grade fuel for power generation. The process of switching off the onboard generators of berthing ships and connecting to shore power is called shore-to-ship power supplies (STSPSs). To comply with mandatory air-pollution requirements, in 2014, the Port of Oakland installed STSPS projects at various berths. In 2015 at Berth 37, a 7.5-megavolt-A (MVA), cast-coil transformer within an outdoor enclosure experienced an arcing of the primary no-load tap connections at 12.47 kV. The installation and testing of Berth 37 complied with the International Electrical Testing Association. It is a normal practice to leave the transformer energized when the STSPS operation is finished. The taps arcing occurred when the transformer was energized without any load. There was no power system transient event when taps arcing occurred.

This paper provides a closer-look at a high resistance grounded (HRG) power system using symmetrical components. It addresses the industry confusion, "how system charging current flow direction reverses during bolted phase-ground fault condition without reversal of system voltage that causes fault current flow". In this paper, the theory of symmetrical components has been used for analysis of phase-ground fault to illustrate ground fault current flow directions and its phasor diagram. The industry concept, "phase-ground fault current flows from the faulted location to ground before it returns to the power source" has been used in the analysis. This concept has not been used in the IEEE Std. 142-2007, causing ground fault protection confusion for HRG power systems. The fault current flow direction clarification will help in the application of a sensitive voltage polarized ground fault protection relay for HRG. Under phase-ground faults with very low arcing fault currents which pose a sensitivity issue on ground fault protection relays, some relevant technical papers providing techniques of fault detection are referenced in this paper. Clarification on the limitation of HRG grounding contained in IEEE Std. 142-2007 for phase-ground fault current not to exceed 10A and power system voltage not to exceed 4.16 kV is also included in this paper.

This paper cites current mandatory requirements in the "Title 30-Mineral Resources, Code of Federal Regulations, "30 CFR 75.814, and MSHA" for the ground fault current protection relay settings and neutral resistor rating for a high-resistance grounded (HRG) underground mining power supply system. Very high system charging current of a mining power system poses design concern of meeting the MSHA requirements, "ground-fault current shall be limited by a neutral grounding resistor (NGR) to 3.75A and associated ground fault protection relay shall be set at 40% of the NGR rating when power system nominal voltage exceeds 2.4 kV". This paper is based upon a published paper with very high system charging current of 68.2A. The previous authors have correctly identified the problems of meeting MSHA requirements; NGR rating and ground fault relay settings. This paper recommends a voltage polarized ground fault current relay that can be set to meet MSHA requirements even if the NGR rating does not meet MSHA requirements. Such a relay identifies forward direction and reverse direction of ground fault current during phase-ground fault condition. The ground fault current flow in the three-line diagram indicates that the faulted feeder relay senses higher ground fault current whereas the parallel feeders and the neutral relay senses less current to cause delayed tripping of NGR relay and parallel feeders relays to improve power system reliability. Per NEC (NFPA 70) code requirement, a movable equipment enclosure grounding to keep voltage less than 100V across the grounding conductor is included. For the underground mine medium-voltage (MV) feeders; the practice of using an integrated continuous monitored ground check wire (with the phase conductors) is explained.

This paper describes design application of 11 kV high-resistances grounding (HRG) protection schemes for the power plant generators to minimize phase-ground fault damage. Generated power is stepped-up to connect to utility grid at 66 kV by transmission lines, and it is stepped-down to 6 kV to supply power to the plant auxiliaries. One HRG protection scheme consists of a generator neutral resistor sized per the HRG criteria and a separate HRG protection scheme designed for the ungrounded 11 kV power system when the generator breaker opens and the utility back-feeds power to the generator auxiliaries. How two separate HRG schemes operate to provide minimum phase-ground fault current is included in this paper. Three-line diagrams are presented to show bolted phase-ground fault conditions' fault current flow directions, equivalent circuit, and phasor diagrams. Discussion on sensitivity of current relays to detect low phase-ground fault and to clear the fault by over voltage relay is included. This paper clarifies that the system charging current under normal operation and during phase-ground fault condition is provided by the power source.

This article reviews low-voltage shore connection (LVSC) power systems for ships with up to 1,500 kVA and voltage of 400-690 V. The design concept for these systems is contained in the current LVSC draft standard, International Electrotechnical Commission (IEC)/IEEE 80005-3. Here, we attempt to clarify that an LVSC design concept using multiple parallel feeder circuit breakers does not violate National Electric Code (NEC) National Fire Protection Association (NFPA) 70 Section 240.8. We also attempt to clarify the optional design for an ungrounded shore power system, as required by certain ships and included in the draft standard [1]. In addition, we review the safety loop circuit that enhances operator safety both onshore and onboard a ship.

This paper clarifies the bolted single-phase-ground fault current flow directions and its' phasor diagram for a high-resistance grounded (HRG) power system. The paper clarifies that the system charging current 3ICO (vector sum of currents from un-faulted phases to ground) flow direction remains unchanged, whereas the same current called the capacitive component of the phase-ground fault current (ICGF) flow is in the reverse direction to 3ICO. This follows the mathematical relationship, ICGF = − 3ICO at the fault location and at the power system neutral. Many publications fail to apply this concept to phasor diagrams of phase-ground fault current, showing the phase-ground fault current power factor lagging, with respect to faulted phase-neutral voltage, which is questionable. Other publications, including the IEEE Std. 142-2007 contains figures of HRG systems that do not use the relationship ICGF = − 3ICO, causing application confusion. This paper recommends use of the relationship ICGF = − 3ICO for HRG power systems and se of “phasor” instead of “vector” to present phase-ground fault currents with respect to faulted phase-neutral voltage, and faulted phase to two un-faulted phases voltages.

This paper reviews low-voltage shore connection power systems for ships with up to 1,500kVA and voltage of 400V to 690V. The design for these systems is contained in the current low-voltage shore connection (LVSC) draft standard IEC/IEEE80005-3. This paper attempts to clarify that a LVSC design that uses multiple parallel feeder circuit breakers is not violating National Electric Code (NEC) National Fire Protection Association (NFPA) 70 Section 240.8. This paper also attempts to clarify the optional design for an ungrounded shore-power system, where required, which is included in the draft standard. In addition, this paper reviews the safety loop circuit to enhance the safety of the operators both onshore and onboard a ship.

This paper describes a retrofit harmonic mitigation solution for the 480V power supply system designed for the battery charging system for the 72 automated guided vehicles (AGVs) at a large container terminal. The individual battery charging system for each AGV consists of 18 six-pulse thyristor modules, with each module rated at 7kW, 40V dc, and an AGV charging capacity of 126kVA at 720V dc. The supplier of the battery and battery charging equipment made no effort to mitigate harmonics and power quality issues in the design of the 480V power system. Design engineers for the container terminal performed a harmonic analysis when the power system design was configured based on the cabling and wiring information provided by the supplier. The analysis showed high harmonics, much higher than the limits prescribed in IEEE Std. 519. To achieve proper operation of the AGVs without affecting other automation equipment at the terminal, active filters were retrofitted. This paper discusses the test results for and limitations of mitigating harmonics for the first phase of retrofitting six active harmonic filters. This paper also provides recommendations for designing the port AGV power system.

Stray current is current that seeks unintended paths through earth and metallic utilities. This current can be from a dc or an ac source. Stray current from an ac source is expected to only produce 1-5% of the corrosion produced by an equivalent amount of dc source. Cathodic protection (CP) is a technique used to control the corrosion of a metal surface by making it the cathode of an electrochemical cell [6]-[8], [11]-[13], [15], [20].

To minimize ground fault during a line-to-ground fault condition, it has been a common practice to use high-resistance grounded (HRG) power systems, both at low voltage and at medium voltage (MV). The criteria for designing HRG systems are very well known to the industry; however, the opinion of industry experts has been divided on limiting the use of HRG systems for MV systems to voltages of less than 4.16 kV and phase-ground fault currents of less than 10 A without clarifying that it applies to systems that require continuous operation upon first detecting line-to-ground fault, as it is now in the Recommended Practice for Grounding of Industrial and Commercial Power Systems. This paper will review the background history of HRG power systems and their application to MV systems for specific industries and will make the case that voltages need not be limited to less than 4.16 kV and the phase-ground fault current to less than 10 A, so long as the faulted power system is isolated within ten cycles and that there are no directly connected motors. This paper will discuss the potential damage and protection requirements of HRG systems for MV applications to ensure that a line-to-ground fault is cleared before it involves other phases to make a multiphase arcing ground fault.

THE NATIONAL ELECTRICAL CODE (NEC) [1] requires that ground-fault protection of equipment be provided when the building service disconnecting rating becomes 1,000 A or higher. To meet such a requirement, generally, the main service breaker is specified with ground-fault protection capability. This type of breaker provides ground-fault protection for faults occurring on its load side but not for faults occurring on the line side. Such ground faults may be on the building transformer secondary windings, including the secondary feeder cable terminations at both ends. This article describes a ground-fault protection relay scheme that can provide low-level arcing, ground-fault current protection of the building transformer secondary, including secondary feeder cables. A discussion is included on meeting the design requirements of NEC 705.12 for the building's 480Y/277V main switchboard (MSB) bus rating when a photovoltaic (PV) ac inverter connection is implemented using a dedicated circuit breaker inside the switchboard.

This paper provides an electrical equivalent circuit of a high-resistance grounded (HRG) power supply transformer to discuss damage at a fault location so long as the fault remains a line-ground fault. Fault resistance and fault current that have an effect on damage are included in the equivalent circuit. Three-line diagrams showing fault current flows along with their vector diagrams are also included. Part II of this paper provides a similar equivalent circuit for an HRG grounded generator. This paper provides guidance to update the current edition of IEEE STD. 142 with respect to HRG systems.

Cold ironing power system design requires unique components to supply shore power to ships for cold ironing operation. Currently, the development of new standards is in progress, and operating procedures are being written to maximize electrical safety, standardization of the process, and interchangeability from one location to another. This article describes the power system design, including a power system protection scheme, which should enhance the electrical safety by design. The power system grounding, equipment grounding, and touch potential that can impact personnel safety are described. A very basic outline of the operating procedures and training needed for the operators to maximize electrical safety during cold ironing operation are also included in this article. In addition, this article provides the current status of the draft International Electrotechnical Commission (IEC)/International Organization for Standardization (ISO)/IE Standards 80005-1 [5] and 80005-2 [6].