Advices on Choosing Statistic Voltage Monitor
Zhang Zhong
Lots of customers had consulted us the choosing of statistic voltage monitor, even those products by invite tenders are not satisfactory. To choose a professional quality and reliable value statistic voltage monitor, we have some advices.
1. Products must meet the DL500-92 electrical industry standard《Technical Requirement for Voltage Monitor Order》
Voltage monitors have a variety of new functions now, such as IC card read-meter, Pocket PC read-meter, MODEM read-meter, GSM / GPRS telecommunication, but all these are built on the most basic condition: DL500-92 electrical industry standard. To meet the standard, manufacturer must take True-RMS sampling. Only in this way, could avoid the appearance of decrement with true value when the voltage waveform distorts.
There is something fishy in True-RMS sampling. To save cost; some manufacturers use other test methods to simulate the TRMS/DC circuit; actually, this leads to lots of troubles. You can see the flaws as the imposition of harmonic.
2. Manufacturer must be measuring implements certificated.
3. The product must pass the Electrical Industry Reactive Power Compensation Package Equipment Quality Inspection Center sample approval test.
The Electrical Industry Reactive Power Compensation Package Equipment Quality Inspection Center is the designated voltage monitor type test center of State Grid Corporation. Any new product of voltage monitor should pass before put into production.
If the manufacturer passed the test, means he has the basically capability to manufacture voltage monitor.
4. Manufacturer should be quality management system certificated.
Only in strict accordance with ISO9001:2000, can pledge the normalization, continuity and traceability of the basic work of business management, so does the before & after service.
Those manufacturers confirmed by Quality and Technical Supervision Bureau could be more reliable.
5. Prospectus to be more detailed, more readable, more standardized and more rigorous.
This is a measure scale of manufacturer’s technical level, also affects the usage of customer.
6. Production technologies to be more sophisticated.
7. The product to be intuitively displayed, easy to control, and the colors to be soft and coordinated.
8. Inspect the function.
Besides the common functions, inspect the software had take everything into consideration or not, such as the setting of check out date, get power cut before monthly check, and so on.
9. Inspect the configuration.
Different configurations lead to different prices. Because voltage monitor should work long term uninterruptedly, to meet the MTBF≥10000h of DL500-92 standard, the circuit device must be highly restricted. Conscientious manufacturers always use the circuit of IC Company; assemble with reasonable software design, circuit design, process design, also in strict accordance with the implementation of high standards in transformers, transformers, switches, wires, radiators and buttons choosing. Do their best to choose suppliers with ISO9000 certificate. Although these will add the prime cost, however, the reliability, stability, meter of cooling conditions is markedly improved, all these aimed to raise the MTBF. Those products with cheaper configurations could be a little bit cheaper, but much worse in quality. Then inspect the configuration became more important in the monitor choosing.
To those statistic voltage monitor work under -20℃ conditions, in order to ensure reliable long-term work, should choose those products using industrial IC circuits and configurations. Customers should understand the need of this improvement.
One electric power bureau carry out tender in the option of voltage monitor, they cover the manufacturer mark, trademark and model, number the products and compare these products in the following aspects:
① the configuration info
② test info of hardware performance
③ test info of software performance
Systematic arrange them with the score, in this way you can find the more comparative product.
10. Inspect the operation result of manufacturer
① investigate the corporate credit over the past contact.
② investigate the condition of manufacturer from the other customers
③ investigate the supply capacity form technology development, after-sales service, operating performance.
11. Brand influence
Voltage monitor market should convert from number expansion and price competition to the quality and brand-based competition. Manufacturer should build up the brand strategy of customer satisfaction, develop effectively and sustainably. This is one of the important condition which affects the choosing of customer.
Customer can choose more qualified voltage monitor by the upper 11 items. In the past tenders, lots of customers pay more attention on price rather than quality. We suggest those conditional and with subject of a large tender, had better to do the full-performance test to tender products, and otherwise could ask the manufacturer to provide the full-performance test report from Electrical Industry Reactive Power Compensation Package Equipment Quality Inspection Center, also can consult professors with manufacturers’ operation result and technical level. After these comprehensive assessments, customers can find those voltage monitors manufacturers with excellent quality and responsible after-sales service.
References:
1. State Power Corporation published 18th [2002] “The announce of transmit 《1998-2001 Voltage Monitor Sample Test Qualified Product List》by. Electrical Industry Reactive Power Compensation Package Equipment Quality Inspection Center”
2. Electrical Industry Reactive Power Compensation Package Equipment Quality Inspection Center 1999 1st《About 1997 Annual Voltage Monitor Quality Test Report》
3. Zhang Zhong Voltage monitor and the development 1993 11th《Electrical Measurement & Instrumentation》
4. Zhang Zhong On the soft design of electronic instruments 1990 9th 《Electrical Measurement & Instrumentation》 |
