In the Soviet time, regulatory lightning protection document RD 34.21.122-87 was developed to determine requirements and criteria to the lightning protection system. However, after the Soviet Union break-up, newly formed republics began to develop their own regulatory documents having their specifics and differences.
This article is dedicated to one of these standards effective in the Republic of Belarus, namely construction standards SN 4.04.03-2020 (hereinafter, SN), which came into effect after its official publication on February 19, 2021. In particular, this is a search for differences from regulatory documents in lightning protection currently effective in the Russian Federation rather than a review of these standards. The main Russian standards are above-mentioned RD 34.21.122-87 (hereinafter, RD), and SO 153-34.21.122-2003 (hereinafter, SO).
Thus, the first aspect we can note is Section 6 describing risk assessment events, which are separated and based on the potential damage resulting from the lightning strike. The damage is classified as follows:
- - people's death or injuries;
- - utilities disruption;
- - cultural heritage loss;
- - economic damage.
Basic Russian standards almost do not mention these assessments, but SN determines risks for each damage type, based on which the decision on the need of lighting protection and its structure is typically taken.
Lightning protection levels in SP as well as in SO are described as I-V for conventional facilities with the reliability being equal to 0.98 to 0.8. At the same time, for substations, the levels correspond to the RD classification, namely levels I-III with the reliability 0.999 to 0.9.
Lightning arrester type definitions are among major differences. SN describes a lightning rod with early streamer emission (ESE) which is chosen according to the procedure provided in Appendix D to SN. Supporters of active lightning protection shall like this. Russian regulatory documents do not consider this type of lightning arrester as allowable.
I was surprised to see the table providing materials and profiles as well as their cross-sections for lightning arresters and current collectors. This solution allows saving time for designers. Recommendations for installing current collectors would make happy even those people who are not engaged in lightning protection, since many options are clearly described.
The choice of lightning arresters in SN differs from the regulatory documents in Russia in that it is similar to the well-known IEC, but protection zones are calculated using the same formulas as in SO. However, there is a principal difference in complex system calculations. SO primarily recommends using a special software via which the lightning arrester height is determined, excluding the simplest systems (single/double lightning arrester, single/double/closed lightning arrester wire). SN recommends using a special software when the calculation should take into account sags or when the ends of a single wire are located at different heights.
In the grounding device section, SN requires a grounding arrangement with the resistance of not more than 10 Ohm (item 7.4.5) for categories I and II of lightning protection, and a minimum grounding electrode length is determined according to the chart provided in Fig. 7.3. To compare, RD establishes reasonable requirements to the grounding arrangement of lightning protection category I according to item 2.2, but this as well as any other (non-industry-specific) regulatory documents do not rate grounding resistance. Moreover, for category II facilities, according to the EIC, item 1.7.55, grounding arrangement of the protective grounding and category II and III lightning protection grounding shall be common. And it means that, for the facilities powered from HVPL, the resistance requirements may come across with the SN requirements.
Materials and cross-sections of grounding arrangements rated in SN are comparable with the Russian regulatory document requirements, and they differ from similar requirements of GOST R 50571.5.54-2013 within an error.
The electromagnetic safety section in SN, as opposed to RD and SO, is much longer since potential equalization events, SDP application, and shielding are detailed there.
In terms of the lightning grounding, SO and SN provide similar recommendations, although in choosing SDPs, SN includes details on installation of SDPs of each class, both at the lightning protection zone boundaries and at the particular installation points; moreover, authors have also included a phrase on the need to comply with the SDP manufacturer's requirements in terms of cable length between the devices. Recommendations correspond to GOST IEC 61643-21-2014 which is effective both in Russia and in the RB.
SN comprises a series of rules to protect air power lines (PL) 110-750 kV (item 10.3.1), 110 kV PL with protected wires (item 10.3.2), 6-35 kV PL (item 10.3.3), 6-10 kV power lines with open wires (item 10.3.4), which are absent in SO and RD but are described in the EIC, Section 2.5, as well as 0.4 kV PL, which are described in the EIC, Section 2.4.
The events on protection of switching devices (item 10.4.1 to 10.5.2) described in SN can be compared to Section 4 of the EIC. Grid cell sizes can be taken as a difference in terms of protection of buildings for closed switchgears and buildings located in the electrical substation. In the Russian regulatory documents, these are category 3 facilities, and the step is 12 m, while SN classifies categories depending on the risks, and the values are 5, 7, and 10 m for lightning protection categories I, II, and III, respectively.
To sum up, we can say that the construction standards that came into effect in the RB on February 19, 2021, are a good collection of information that includes not only major data on events related to choosing the lighting protection equipment, lightning arrester calculation, but also detailed recommendations in terms of choosing materials, location of current collectors, providing events on potential equalization, choosing SDPs, and shielding. Information on the protection of air power lines and switching devices supplements this document.
A significant difference from the Russian standards is that a single document combines almost all information on lightning protection and grounding, which makes it multi-purpose. However, it is important that SN allows using solutions with active lightning arresters which are not defined as a protection method in the Russian regulatory documents.
Moreover, an approach to define the need to perform lightning protection in general and determine its class for the facilities via risk analysis reminds us that the economy is not the least important issue in design. However, a clear classification of facilities for the lightning protection level is lacking from this document as well as from SO; therefore, the EIC and RD will likely be of some help in this respect. In other respects, SN requirements represent almost the same requirements as the Russian regulatory documents, if we use them together.
When you need to calculate the lightning protection and grounding system for any facility according to effective regulatory documents, you can always contact the ZANDZ Technical Center.