National Center for High Voltage Measurement (NCHVM)

I. Overview
Established in 1974 under the sponsorship of State Grid Corporation of China (SGCC) and operating on the basis of China Electric Power Research Institute (CEPRI), the National Center for High Voltage Measurement (NCHVM) is engaged in statutory high voltage and heavy current measurement verification nationwide as authorized by the General Administration of Quality Supervision, Inspection and Quarantine (AQSIQ). It is the only national statutory authority in electric power industry authorized by AQSIQ and preserving the national standards of measurement in electromagnetic field. In 2000, NCHVM became the first laboratory accredited by CNAS in the electric power industry; In 2001, it became the first institution in China to pass the metrological authorization and assessment of AQSIQ. NCHVM is currently the Chinese Secretariat of IEC/TC42 as well as Secretariat of the Technical Sub-Committee for National High Voltage Measurement and the Technical Sub-Committee for National Standardization of High-Voltage Test.

II. Main Duties

Preserve and maintain the national high voltage and heavy current references and the highest national standards, and carry out value transfer nationwide according to law; undertake relevant metrological supervision and arbitration work issued by the governmental administrative departments for measurement; carry out research, popularization and application of new measurement technology; take responsibility for drafting specifications and regulations for measurement technology in high voltage and heavy current sectors.

III. Reference Standards
Establish 1 national reference measurement standard and 9 public measurement standards, and establish a full set of measurement standard system for high voltage and heavy current values of power frequency, DC and impulse in China.

IV. Calibration Capability
44 calibration items approved by CNAS are available. Capable of conducting calibration on power frequency voltage ratio standard and transformer within 10V-1000kV, and calibration on power frequency current ratio standard, current transformer and current sensor within 0.01A-60kA; Capable of conducting calibration on all kinds of DC voltage standards and equipment within 1kV-1000kV; Capable of conducting calibration on all kinds of DC current standards and equipment within 5A-50kA; Capable of conducting calibration on more than 20 kinds of test equipments for high voltage test and insulation preventive test such as DC resistance tester, variable ratio tester, digital HV meter, high-voltage switch tester, etc.; Capable of conducting calibration on digital metering equipment in smart grid and flexible DC power transmission, such as electronic transformer, merging unit, etc. NCHVM was authorized by AQSIQ for energy efficiency labeling testing of high voltage motors and power transformers respectively in 2013 and 2016; the full-performance testing platform of low-voltage metering current transformer has been established to carry out testing work comprehensively. 

Tab.1 List of Main CMC Capacities of NCHVM

No.	Calibration or Measurement Service	Measuring Range	CMC (k=2)
1	Power frequency current ratio	0 ~ 60000A	ratio error: 0.28×10-6 ~ 6.0×10-6 phase displacement: 0.28×10-6rad ~ 6.0×10-5rad
2	Power frequency voltage ratio	10 kV ~ 1000/√3 kV	ratio error: 1.2×10-6 ~ 3.3×10-5 phase displacement: 1.2×10-6rad ~ 3.3×10-5rad
3	DC current ratio	0 ~ 50000A	ratio error: 0.6×10-6 ~ 2.4×10-6
4	DC voltage ratio	1 kV ~ 1000kV	ratio error: 5×10-5 ~ 2×10-4
5	Impulse voltage	20 kV ~ 2500kV	1.3×10-2 ~ 1.7×10-2
6	Impulse current	2 kA~100kA	1×10-2

V. International Cooperation
With the great support and active coordination of AQSIQ, NCHVM and National Metrology Institute of Germany (PTB) has reached a long-term cooperation agreement, and established normal communication with PTB. In 2011and 2014, NCHVM dispatched 4 technicians to PTB to carry out a half-year research. In 2015, NCHVM compared its measurement standards with PTB.

As the Chinese Secretariat of IEC/TC42 (High-voltage and high-current test techniques), NCHVM has participated in drafting and maintaining standards of WG 19, WG 20 and MT 12, and has made contributions to international standards like IEC60060, IEC 61083, IEC 62475, etc.