Investigation on KPI for self-healing smart distribution system operation cockpit

Kang Taifeng, Ge Liang, Tan zhihai, Zhao Fengqing Business Department of Distribution Network

Beijing Sifang Automation CO., LTD. Beijing, China

taifeng.kang@gmail.com

Dong Xuzhu Electric Power Research Institute

China Southern Power Grid Guangzhou, China

Abstract—as society and economic rely highly on power supply. The self-healing smart distribution system is the ideal solution to solve the conflicts between society requirement and development of power grid. In such system, there are a lot of distributed energy resources (DER), such as new energy resources (wind turbine, photovoltaic, storage device) and small client site generators, which play important roles by enhancing client site reliability, deferring property investment. However, as more information bursts into control center, the work for operators turns out complex. The conceptual operation cockpit which origins from aerospace is raised to help better understand the system running level and make effectively operational decision. In this article, we investigate on the key performance indicators (KPI) for self-healing systems and operation cockpit based on balanced scorecard (BSC). With the KPI system, operators can obtain the self-healing and smart distribution system performance and situation from a higher, system and business prospective, and they can get better understand and operational decision support. The work in this article is useful for evaluation of self-healing smart distribution and can direct the application of operation cockpit.

Keywords—smart distribution system; self-healing; key performance indicator(KPI); operation cockpit; balanced scorecard

I. INTRODUCTION As society and economic rely highly on power supply,

active and self-healing have become the core emerging conceptions for smart distribution network [1]-[4]. In this distribution network, distributed energy resource (DER), such as new energy resources (wind turbine, photovoltaic), and small client site generators, has become more and more popular. DER plays important roles in smart distribution network such as enhancing client site reliability, deferring property investment. To accommodation of DER, the system has to perform more active from planning to the operation with the requirements of DERs. Besides, the security and reliability of distribution network have drawn more attentions than ever. Self-healing has turned out as the first choice for large scale distribution network, which can proactively find and diagnose failures in the network, solve security issues in closed loop providing more smart and intelligent ways to enhance reliability.

However, complex self-healing and smart distribution

system burdens the operators a lot as there is more data and information burst into the control center especially when fierce event occurs. System operators are often required to make decision in very short time when events happened to the system. How to help operator effectively and quickly obtain key system operation situation and make smarter decision is a challenging research topic. Referring to the cockpit original from aerospace, operation cockpit is raised. Based on graphic and visualization technologies, operation cockpit works as a highly integrated system where system key operational information is presented and supporting decision and control is available. With operation cockpit, operators can contribute their work on a single component which will reduce their work load and complexity.

One of key issues for applications of such operation cockpit is the organization and presentation of important high level operation information. In this article, we investigate on this topic by proposing a suit of key performance indicators (KPI) based on balanced scorecard (BSC). With the KPI system, operators can obtain the self-healing and smart distribution system operation’s running level and situation from a higher, system and business prospect, and they can get better understand and operational guidance.

II. SELF-HEALING SMART DISTRIBUTION NETWORK AND OPERATION COCKPIT

A. Self-healing smart distribution system Large penetration of distributed energy resources and new

way for operation and management such as demand side management or demand and response (DR), make distribution smarter. In smart distribution system, distributed energy resources could provide extended reliability and clean energy to system users; our clients could choose use electricity more efficient and economical way by interaction with system; new type of energy consumption is supported, such as electric vehicle. Smart distributed system is high reliable, high efficient, clean, economical and flexible.

Self-healing is one of the key solutions for high reliable and efficient smart distribution system. Self-healing is a proactive way to solve threatens from inner and outside of the system. In general situation, the self-healing system perspective percept the risk and threaten, searching for the best way to avoid

This work is supported by National High Technology Research and Development Program of China (863 Program) (No. 2011AA05A114).

978-1-4799-2827-9/13/$31.00 ©2013 IEEE978-1-4799-2827-9/13/$31.00 ©2013 IEEE

upcoming uncertainty by refactoring ; In extreme situation such as fault occurs, it automatically searching the best way to clear faults and restore service as soon as possible.

B. Operation cockpit The conception of ‘Operation cockpit’ origins from

aerospace cockpit [5]. In the cockpit, different kinds of data meters and control panels are located in limited space which provide one-stop way to integrative manage and control.

Management cockpit system extends original cockpit idea. It is a complex information system by integration of information from different systems to investigate on the operation performance which is represent in Key Performance Indicator (KPI) by vivid ways such as dashboard, radar chart or meters. Based on the management cockpit and KPI system, diagnosis and data mining solutions are available for finding the cause for underperformance behaviors and enhancing the overall performance. The key technologies and infrastructure to maximum utilize the operation cockpit include: research and design of the KPI system, adoption of suitable data and information visualization technologies and decision support system.

The Operation cockpit [6] is kind of management cockpit which represent the whole picture of system operation performance in visualization manner and provide integrative management, control and decision support. Operation cockpit can help operators get better understand of the system, quick operation decision support in a more vivid and intuitional way.

III. BSC BASED KPI FOR OPERATION COCKPIT KPI system is the key composition of operation cockpit.

Traditional KPI lacks systematic directory and design which usually based on the assessment and audit for particular business. And it lacks comprehensive supervisory of the whole business and it is often subject to part of operation performance and specific projects.

In this section, we will borrow the mature system from Balanced scorecard (BSC) [7] to build KPI for operation cockpit, which pays attention to systematic, comprehensive and balanced performance indexes. The proposed KPI system will help grid security, stable and sustainable operate and develop.

A. Balanced scorecard Balanced scorecard (BSC) origins from company and

business management. It is useful for strategy planning and performance management. The BSC synthetically manage and control the strategic goals of not only business but also other processes which support business success, such as internal and external process, and the sustained growing ability. It provides actual way and guidance for the managers to align their activities to achieve the strategic goals.

It is composed of four perspectives, financial perspective, customer perspective, internal process perspective, and learning and growth perspective, which have been shown in Fig. 1.

• Financial perspective contains the financial index such as income, asset profit rate, which reflects the

economical performance for company or organization. Timely and accurate financial index is always the key reference for the executive to make strategic decisions.

• Customer perspective contains customer orientated service and corresponding indexes, such as customer satisfaction rate, customer complaint rate. In modern business, the relationship with customer is the important index for performance rating.

• Internal process perspective contains the indexes for internal department and business related performance which describes the importance of internal business capabilities for an enterprise or community to achieve success.

• Learning and growth perspective contains the indexes of employees, culture, information technologies other supporting factors which help sustainable success.

Fig. 1. Balanced scorecard conception model

Fig. 2. Proposed BSC based KPI system

B. Balanced scorecard based KPI for smart distribution system

Balanced scorecard is one of the best tools to rate the business and management level for a company or community. However, distribution system is a little different from that. Distribution system stakeholders pay attention not only financial perspective, but also social responsibilities. The KPIs related to social responsibilities include system reliability, sustainability development and good customer satisfaction.

For operation cockpit, the internal process aligns to different aspects for grid operation, and relative KPI should

focus on the key operation performance indexes according to the aspects of grid operation.

For the ‘learning and growth’ perspective, we focus on supports for security, stable, economical and sustainable development of distributed system. So relative KPI system should pay attention to such aspects and indexes, which include advanced devices, information technology and employee development.

From above considerations, we propose BSC based KPI system shown in Fig. 2.

TABLE I. KPI FOR SELF-HELING DISTRIBUTION SYSTEM COCKPIT

Perspective Indexes

First-level indexes Second-level indexes Description& formulas

Performance perspective

System reliability

System Average Interruption Frequency

Index, SAIFI Customer interruption times/ total customers in district

System Average Interruption Duration

Index, SAIDI

Total customer interruption durations/total customers in district

System reliability rate (1-customer average interruption duration/total duration) ×100%

Economical Line loss rate (power energy supplied-power energy sold)/power energy supplied×100%

Sustainability CO2 reduced Total CO2 reduced by clean distributed energy resources

Customer perspective Customer satisfaction Customer complaint rate Amount of complained customers/total customers×100%

Internal prcess perspective

System structure

10kV line heavy load rate Amount of heavy load lines/total lines×100%. Heavy load

line: the top loading rate is equal or over 70% and lasting for more than 1 hours per year, except for transferred way

10kV transformer heavy load rate

Amount of heavy load transformers/total transformers×100%. Heavy load transformer: the top loading rate is equal

or over 80% and lasting for more than 2 hours per year Load per section for 10kV lines Total line load/sections in line

Distribution automation Feeder automation accuracy rate

Accurate feeder automation action times/total feeder automation action times×100%

Self-healing Self-healing success rate Accurate self-healing action times/total self-healing action times×100%

Microgrid operation Islanding operation times Times for microgrid islanding operation times

Power quality

Voltage eligibility rate Sum of eligible voltage/total voltages×100%

Three phase voltage imbalance

Negative sequence voltage/ positive sequence voltages×100%

Voltage distorted rate Amplitude of fundamental waveform /root mean square of harmonic waveform×100%

Learning and growth perspective

Human resource Employee satisfaction rate Amount of satisfied employees/surveyed employees×100%

Advanced devices Cable line rate Total cable line length/total line length(cable and overhead

line) ×100% Cable line fault rate Cable line fault times per 100km cable line

Informatization key process Informatization rate

Amount of key Informatization process/total key process×100%

C. KPI selection • Performance perspective: The KPIs in performance are

the indexes which mostly draw the attention from the system operators and stakeholders. In this section, we focus on different requirements and anticipations from both inside and outside system, including reliability, economical and sustainability. These KPIs are

generally typical high level performance indexes, and they are not only available for system supervisory, but also for comparison among different distribution systems. The KPIs for performance perspective are listed in table I.

• Custom perspective: this perspective pays attentions to custom service procedure and capabilities. According to the business for customer services. Although there

are many procedures, such as fault call-in, new custom connection, for operation cockpit, the key concern for operators is customer satisfaction index. And customer satisfaction is the key index for this perspective.

• Internal process perspective: Internal process perspective pays attentions to the details of system operation, which include system structure, distribution automation, self-healing, microgrid operation and power quality. There are secondary indexes for different categories.

• Learning and growth perspective: this perspective considers the factors support and affecting system security, stable and sustainable development. The indexes in this part relate to human resource, advanced devices and Informatization.

IV. CONCLUSION In this article, we review the original of cockpit and reveal

the advantage of the operation cockpit for self-healing smart distribution system. Then we investigate on the key performance indicator (KPI) system for such operation cockpit based on the balanced scorecard (BSC). The KPI system is composed of four perspectives, performance perspective, customer service perspective, internal process perspective and sustainable development perspective. Different indexes are elected according to the corresponding perspective of the self-healing smart distribution.

The work in this article is useful for evaluation of self-healing smart distribution. Based on BSC, the KPI system is very flexible and can be extended in different perspectives. The work can guide the application of operation cockpit and has been applied into real self-healing smart distribution system project.

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