From December 26 to 27, 2020, Nanjing Electric Insulator Co., Ltd. hosted a verification meeting in Nanjing for its glass insulators that have been in service for 55 and 30 years. The event brought together experts from the Xi’an High Voltage Apparatus Research Institute, the China Electric Power Research Institute, State Grid operating units, as well as representatives from the company. Under the witness of authoritative experts, industry leaders, and user representatives, the mechanical and electrical performance tests were successfully completed, with results fully compliant with national standards—once again demonstrating the excellent aging‑resistant performance of Nanjing Electric’s “Leidian” brand glass insulators.

The LXP‑60 glass insulators manufactured by Nanjing Electric Insulator Co., Ltd. (formerly Nanjing Electric (Group) Co., Ltd., and previously known as the Nanjing Electrical Porcelain Factory) have been in service on the 220 kV Jixi–Boli transmission line for 55 years, while the LXP‑100 and LXP‑160 glass insulators have operated on the 330 kV Jinzha No. 1 line for 30 years. To evaluate the electromechanical performance of these three types of glass insulators after prolonged service, samples were collected and returned to the company for experimental verification.

The product testing and verification meeting was held in the company’s Conference Room No. 3. At the outset, company leaders delivered welcoming remarks to all attendees and outlined the development history of glass insulators. Representatives from Ankang Power Supply Company reported on the commissioning and construction of the 330 kV Jinzuo Line I, as well as on the operational performance of glass insulators over the past 30 years. Due to the COVID‑19 pandemic, representatives from Jixi Power Supply Company were unable to attend in person; they presented, via video link, the 55-year operational record of glass insulators on the 220 kV Jibo Line. The annual self‑breakage rate of glass insulators on both lines has remained consistently at a level of several parts per ten thousand. A representative from the Insulator Quality Inspection and Testing Center announced that the sampling test results for three batches of glass products all met the technical requirements stipulated by national standards. Meanwhile, the manufacturer’s representative explained that, over more than four decades, samples drawn from 19 transmission lines—operating at voltages ranging from 110 kV to 500 kV—totaling 900,000 insulators, had undergone 42 rounds of verification testing, yielding over one thousand sets of test data.

During the meeting, the representative from the China Academy of Electrical Sciences spoke first, commending Nanjing Electric for decades of conducting on‑line sampling and verification tests on glass insulators in accordance with national standards. This steadfast commitment is highly commendable and sets the company apart as the only domestic insulator manufacturer to maintain such a consistent approach.

The delegates unanimously agreed that the three glass products sampled—LXP‑60, LXP‑100, and LXP‑160—were developed and manufactured through self-reliance during a period of technological blockade. Although these products have certain shortcomings and are not yet fully refined, their quality levels all meet the technical requirements of the current national standards, which is commendable. In particular, the successful completion of the demonstration tests for thermal cycling, steep‑wave, and impact resistance has reassured power‑system users to continue using them with confidence. The delegates also highly praised Nanjing Electric for more than fifty years of consistently conducting performance‑tracking tests and quality analyses on its in‑service products, a practice that underscores the company’s strong sense of responsibility toward product quality and the safety of power‑system operations.