建築服務工程的成本降低

主要增加的能源成本是讓電力能源成為主要的供電來源。擺脫成本陷阱的第一步就是精確地收集所有能源數據、電器和電子參數。在你自己的能源供應裡,現代能源測量技術需要擁有至少一定程度的透明度存在。概念可在數據基礎上發展,例如電力成本降低和測量的引用。這些針對性的修正也可以被監控與記錄下來。

建築設施管理內,擁有許多大量成本節約的潛力。一個重要的成本因素是廠房和設備、建築與基礎設施的電費。但是電費僅僅是一部分立刻顯而易見的成本,當考慮到一個 '骯髒' 和不穩定的供應電力可能會造成更高。隨著直接電力成本,有效利用電力分配設施和可靠的電力供應設備在經濟效益上扮演著重要的角色。由於這些費用並不是那麼明顯,因此他們也被稱之為"隱藏成本"。

藉由現代電力分析儀來實現成本節省:

  • 減少電能消耗
  • 無功功率成本減少(提高功率因數,減少罰款)
  • 消除最大需量電費
  • 辨識出系統中的高消耗環節
  • 減少維護成本
  • 延長電氣和電子設備的生命週期
  • 每個成本中心精確地登陸需求(例如這辦公室使用了多少電力?)
  • 穩定的電力供應,以保護電腦設備
  • 主動積極測量,意味著配電系統擁有更高的透明度

電力成本減少 - 來自德國的實際範例

直接,消費導向的能源成本將會顯著地減少:

  1. 對物產管理來說,這意味著更高精準度的二級電費計量(成本 - 中心 - 管理)
  2. 藉由適當的電力測量工程,能源消耗報告可以輕鬆地產生,好驗證來自電力程序的電費。這提供了一個很棒的工具,實現更準確地電能消耗資料,並採購更合理的電力來源,減少電費開支
  3. 綜合電力管理系統,覆蓋整個電力供應和負載網路,方便查出高功耗、低效率的設備和環節,實現運行系統的視覺化,並針對問題,提出改進方案與對策。如下圖2所示:

峰值負載監控

在輸入變壓器的饋線處,使用UMG507E 電力分析儀(請見圖3)。
Priority hear was the monitoring of load profiles and power quality parameters (short term interruptions,harmonic loading, unbalanced loading, ...) as well as peak demand supervision. By temporary switching-off consumers, e.g., in the canteen kitchen, it was possible to lower the effective power maximum (demand), reducing the demand charges and consequently the
electricity bill by up to 20%. The 400V sub-feeders to the individual offices and building sections were monitored using UMG96S power analyzers (see Pic 3) with interface and field bus communication. That improved the transparency and facilitated the corresponding allocation of the consumed electricity to the individual cost centres and tenants.

“For us the highest importance was allocating the individual electricity
costs to the individual cost centres in order to create the awareness
with departments and people in order to make a first step in
energy saving. Furthermore, exact knowledge of the power consumption
of individual consumers or consumer groups helped us a
lot in discovering inefficient electrical loads (consumers) and in
initiating countermeasures in energy saving.”

 

 

Get informed anywhere and anytime via email and homepage

On top of that, networking the meters through a field bus enables automatic measurements downloading and makes them available for utilization in network control as well as for the management. To keep installation costs down (e.g., peripheries for the field busses), the decision fell in favour of Ethernet TCP/IP as the backbone for data communications. As network analyzers with Ethernet interfaces are expensive to acquire, and in companies sometimes monthly fees for each LAN point arise, one originally doubted that this could be implemented with the available budget. The solution was to combine the UMG507E network analyzers with a Modbus gateway feature and the UMG96S Modbus devices, see Pic. 8 below. With that, one adapted the high-end UMG507E in the central feeding points to the increased requirements placed on the measurement technology. Simultaneously, with the UMG507E it was possible to connect the more economical UMG96S devices via Modbus to the Ethernet through the Modbus gateway function. The EtherModbus gateway allows serial Modbus to communicate and interoperate with Modbus/TCP devices. The Modbus standard protocol is an asynchronous protocol designed to connect directly to computer asynchronous ports. Modbus has been extended to operate over Ethernet using the IP protocol suite. The Modbus gateway of the UMG507E converts between the Modbus TCP/IP protocol and Modbus RTU protocols transparently. With this method it is possible to combine field busses with Ethernet, which is growing rapidly, and showing it’s strength is reliability, speed and availability.

Get informed anywhere and anytime via email and homepage

Nearly everyone has experienced it: barely out of the office and the first calls come about problems in the computers, computers are failing or the power supply crashes – the web server integrated in the power analyzers create direct access to the data at the individual measuring points. All authorized employees in the electrics department and the management can quickly get extensively informed directly through the homepage of each power analyzer. All you need to do that is a web browser and the IP addresses in the network assigned to each power analyzer. With the latest product development, the UMG604, even a complete costing tool has been implemented with the homepage.

Collect, save and analyze data

The data gained from the various measuring points needed to be collected, saved, processed, visualized and made available. One first tool here is the topology view to get an overview of the running application. Measurement data can be freely selected and limits set to give a fast optical indication of any critical situation. Online analysis tools for graphic analysis of the data, e.g., comparing load curves as well as analysis tools for historical data and report generation were installed. The measuring points were placed on the topology views and now provide a quick overview of the entire power distribution system. It is possible to localize network malfunctions by comparing the individual measuring points and in order to check the defined tolerances at a glance. By storing graphics files (e.g. JPG) with circuit diagrams and building plans, and by linking the associated meters with drag and drop to their actual locations, one can implement a cost effective and customer specific solution. Out of limit conditions (e.g. THD-V too high!) and conditions in the inputs and outputs can also be displayed.

A mySQL database was installed to save the data. The availability of historic data makes it simple for the electrics department employees to create load curves for the procurement department for negotiating with the public utility.

As costly electric supply interruptions had already occurred in the past, great importance was placed on a high degree of data reliability. For that reason, a separate data server with correspondingly high speed and redundancy was used in the data backups. The PSWprofessional energymanagement software was installed on the client computers in the electrics department and in the pro-curement department.

Online values and analyzing historical data

The graphic continuous-line recorder feature makes quick online display of selected measurements feasible. The chart in this function is continuously expanded with new measurements. By analyzing historical data, just a few mouse clicks are needed for, e.g., fault analysis by comparing various parameters.

Future prospects

By integrating functionalities, modern power analyzers are advancing far beyond the limits of digital multimeters, e.g. including following functions all in one devi

  • Energy meter (kWh, kVArh)
  • Harmonic analyzer
  • Transient recorder
  • Event recorder
  • Demand controller
  • PLC functions
  • Data logger
  • Condition monitoring

Rapid improvements in the field of integrated circuits permit continuously faster and compacter network analyzers at affordable prices. So the brand-new UMG604 power analyzer, equipped with a 500MHz DSP (digital signal processor), is a power analyzer that is exceedingly fast and powerful while maintaining the smallest dimensions.

Constantly sampling the eight channels with 20kHz per channel facilitates registering all electrical parameters (more than 800 values), min and max values, the basic power quality values such as harmonic content (up to 40th, per phase with direction detection) and short term voltage interruptions.

Even transients (> 50μs) can be reliably identified. By using modern communication architectures, integrated web servers and the supplied GridVis network analyzer software, comprehensive smart energy management systems (SEMS) for detecting and repairing potential power supply problems - often even before the fact happens - can be generated.

Typical applications:

  • Office buildings
  • Commercial buildings
  • Shopping malls
  • IT and data centre
  • Banks and insurances
  • Hotels
  • Universities
  • Hospitals
  • Infrastructure buildings

Customer benefits of Power Quality Monitoring in Building Management:

 

  • Reduction of electricity cost
    • kWh cost
    • high peak demand charges
    • low Power Factor penalties
    • Sub billing to tenants
  • Sub billing to tenants
  • Avoiding overload of energy distribution system, e.g. tripping of breakers or protection system
  • Power quality improvement
  • Transparency of energy distribution systems
  • Possible lower dimensioning of electrical distribution equipment, e.g. less UPS systems
  • Root cause analysis of power quality problems
  • Precise demand forecast allows improved energy supply contracts
  • Remote monitoring