D 4.5.81 (11)
8.1.2013
D 4.5.8
Common process oriented methodology and tools for building integrated ICT infrastructures in Smart Grid environment
Version 1.0
Created: / 2013-01-08By: / Joni Aalto, Empower IM Oy
Jan Segerstam, Empower IM Oy
Table of Contents
1.Preface
2.Introduction
3.Smart fault management in the low voltage network
3.1.Management of the zero fault
3.2.Management of the phase fault
3.3.Management of a broken medium voltage line
3.4.Management of a changed phase order
3.5.Request for customer site information
4.Continuation of the work
1.Preface
This report is a part of the results from the third funding period of the Finnish national research project”Smart Grids and Energy Markets”. The project has been funded by Tekes – the Finnish Funding Agency for Technology and Innovation.This document is mainly based on the process workshops between Empower IM Oy and Kymenlaakson Sähkö Oy. The goal for the workshops was to describe the processes related to the smart fault management in low voltage network and to recognize the systems which would be required in the processes. The workshops were carried out in cooperation with multiple specialists. The workshops were based on the end customer needs and requirements which means for example reliable power delivery and good customer service in a case of disturbances.
The target for SGEM FP3 Task 4.5.2B is to develop operation models which can be used in co-operational networks including the DSO and a service provider network. The focus is on the smart fault management inthe low voltage network.As a demonstration, this deliverable describes the most essential processes related to smart fault management in the low voltage network and the most important identified phases of these processes. These processes form a base for the future development work as DSO’s, service providers’ and system providers’ integrated systems provide a diverse development platform to further improve the handling of the different processes.
2.Introduction
Remotely readable AMR meters are currently being installed by the DSOs. In Finland, most of the old metering devices will be replaced with a smart meter before the end of 2013. In practice, DSOs needed to choose whether they want to implement the smart meter roll-out by themselves and manage the new AMR infrastructure and the new information related to it, or would they use service providers instead. Task 4.5.2B focuses on the latter option, when the AMR infrastructure is operated as a service based functionality.
In a co-operational company network the goal is to secure cost-effective and profitable operation to all parties. This requires that single operations must be carried out efficiently through the company network. Interaction and continuous communication is a vital part of the co-operation networks and therefore it should be underlined. The figure 1 introduces the development process of a new service, which in this example case is the development of smart fault management processes of a DSO. Blue parts refer to the actions of a DSO while the red parts illustrate the responsibilities of a service provider.
Figure 1. The project scope of the SGEM Task 4.5.2B.
Ultimately, a demand for a new service is based on the identified end customer needs. These needs form a basis for the specification of a new service. In order to be able to build new services by using an integrated ICT infrastructure as a platform, the whole partner network must have a coherent picture about the required measures.
Therefore, the processes of the new service are described and walked through with the different partners to map out the potential flaws already in the planning phase. A service description and a service agreement between the parties are used to make sure that all the required systems are capable of producing the required part of the service and that the parties are committed to run the part of the service with a sufficient quality level.
During the establishment project of a new service the service provider is responsible for the DSO about the quality of the work. Similarly,during the production phase the correct functioning of the service must be ensured by the service provider. Still, the DSO has the overall responsibility towards the end customers. Therefore, it must have the tools to monitor the service and that the service level is maintained at agreed level. Commonly, SLA (Service Level Agreement) levels are agreed between the DSO and the service provider. These define the acceptaple quality level for the different functionalities related to a certain service.
3.Smart fault management in the low voltage network
Previously, metering devices have been mainly used to provide necessary consumption readings to be able to invoice the end customers for the electricity consumption. Therefore, the metering devices have been used to provide information only when needed. The implementation of smart meters is changing the interaction between the metering devices and the DSOs. The new functionalities of the smart meters enable the metering devices to actively inform about the situation in the customer premises and to send notifications if desired.
Therefore, the DSO will have a better understanding about the network situation also in the low voltage network. In addition to the spontaneous alarms the DSOs have a possibility to run queries for a certain number of metering points to acquire more precise status information of a certain network area. The efficient and correctly timed actions during the fault situations will improve the safety of the end customers as well as quality of power delivery. Once the most important fault management processes are identified and described it is possible to use the descriptions as a tool to optimize the operation during the fault situations.
The most important fault management processes which were identified in the process workshops are illustrated in the figure 2. Once the AMR delivery is based on a service concept, the efficient process management requires co-operation between the systems and equipment of the DSO and the service provider as well as their subcontractors. Customer service, network operation center and field working groups need to work as a whole, while the monitoring of correct data transfer and system operability play also a significant role.
Figure 2. Fault management processes of a DSO.
The fault management processes require utilization of the smart meters and reading systems which deliver the information from the meter to the DMS (Distribution Management System), which provides a coherent view about the network situation based on the information which is provided by the network information system, network automation and the metering devices. Next, the steps which are required to handle the different fault situations in a smart grid environment are presented.
3.1.Management of the zero fault
The zero fault is one of the fault types in the low voltage network. Thezero fault can be caused by a broken neutral wire and it can cause harm to the end customer’s equipment or may even danger his life. This is because in a case of the zero fault the metal surfaces of the electrical equipment can have a dangerously high voltage level. Usually the zero fault causes the voltage levels to fluctuate between the phases. This can cause the lights to non-regularly brighten up during the fault situation. Zero faults are commonly noticed in older properties during the major disturbances like storms. The process of managing the zero fault is introduced in the figure 3.
Figure 3.Management of the zero fault.
In this example case the zero fault is managed by usign an automatic disconnection functionality of the smart meter. This way the time which the end customer is exposed to the zero fault is minimized. This kind of functionality sets requirements for the metering devices as the detection of a zero fault must be based on the reliable algorithms in order to avoid unnecessary disconnections.
During the larger disturbances (e.g. storms) the medium voltage faults are repaired first. Due to this, the faults in the low voltage network, including zero faults, are repaired with a delay. On the other hand, in most of the cases the medium voltage fault is the reason for the zero fault. Efficient management of zero faults increase the safety of the end customers and decreases the risk of property damages.
3.2.Management of the phase fault
The phase fault causes the voltage level to fall down in one of the phases. This fault can be caused for example by a blown intermediate fuse or by a broken line. The metering device detects the phase fault by identifying a major voltage level drop in one of the phases. The DSO can analyze the potential cause for the fault by analyzing the arriving alarms from a certain part of the low voltage network or by activating requests for customer site information, which are introduced in the chapter 3.5.
The goal for this functionality is to recognize the faults in the low voltage network. Therefore, the metering device must only send the alarm if there is one or two phases missing. Once all of the three phases are lost, it most likely indicates a fault in the medium voltage network.The steps of management of the phase fault are presented in the figure 4.
Figure 4. Management of the phase fault.
The end customer is informed about the cause of the fault as well as the estimated repairing time. This reduces the need for the end customer to call to the DSO’s customer service in order to enquire the reason for the interruption in the power delivery. Furthermore, this reduces the work load of the customer service during the major disturbances.
3.3.Management of a broken medium voltage line
The utilization of the alarming features of the smart meters allows also to detect and locate the broken medium voltage lines. Typically a broken medium voltage line causes two phases to have an under voltage situation in the low voltage side. By comparing the arriving spontaneous alarms as well as by utilizing the requests for customer site information the broken medium voltage line can be located between certain secondary transformers. The phases of management of a broken medium voltage line fault are introduced in the figure 5.
Figure 5.Management of a fault caused by a broken medium voltage line.
Usually this kind of functionality should not be activated on all of the metering devices below a single transformer. This is because a potentially high number of alarms which would be received in a case of a fault in the medium voltage network. This could cause challenges for the communication devices and networks which deliver the alarm notifications.
3.4.Management of a changed phase order
Changed phase order can cause significant inconvenience for the end customer and for the end customer’s equipment. Changed phase order affects especially rotating electrical equipment as it changes the rotation direction. This can cause incorrect functioning of the device or even break the device. Therefore, also in this fault situation, the fast operation to detect and repair the fault is important. The figure 6 introduces the process of managing the changed phase order.
Figure 6.Management of changed phase order.
Changed phase order is not among the most common faults in the low voltage network. Still, the possibility to receive an alarm about this fault provides the possibility for fast reaction and therefore fast repairing of the fault. Again, this reduces the threat for damages in the end customer premises.
3.5.Request for customer site information
Two-way communication with the metering devices enable not only to receive spontaneous alarms in a case of a fault, but also to activate requests from the DSO’s DMS system to be able to get a more precise information about the situation on a certain part of the low voltage network. Usually the request is targeted to a certain number of metering points. The information which is requested can include for example the information about the momentary phase voltage and/or current values as well as the active alarm events. By analyzing this information the staff of the DSO’s control room can create a more comprehensive picture about the low voltage network situation.
Figure 7. Request for customer site information.
Requests for customer site information can be activated by a staff of the DSOs control room, but it is also possible that the requestsare activated automatically by the DMS system. In this case the requests are utilized in a case of an alarm(s) from a certain part of the low voltage network to identify the situation in the rest of the metering points on the same network area.
4.Continuation of the work
This report introduced the operational processes related to the smart fault management in the low voltage network. Modern metering devices bring multiple benefits to the DSO from this point of view, when comparing to the situation before the smart meter roll-out. The delay between the occurrence of a fault in the low voltage network and when it is noticed by the DSO will be significantly reduced meanwhile the end customers are better informed about the cause for the interruption in power supply as well as the possible duration of the fault situation. Also, the security of the end customers will be improved as there is a possibility to enable the metering devices to automatically switch off the power supply in a case of potentially life-threatening faults like zero faults.
Part of the results of the workshops was the processes described in this report. Additionally, the systems which would be required to operate the processes as well as the required functionalities related to them were identified. The overall system infrastructure is based on the field equipment and the systems of the DSO and the service provider. This part ofthe work will be described in a separate deliverable “Integrated ICT infrastructure in Smart Grid environment”.
CLEEN OY Eteläranta 10, P.O. BOX 10, FI-00131 HELSINKI, FINLAND